The skyline of Passau is dominated by two buildings that owe their existence to the prince-bishops who ruled the city until 1803: the great fortress looming on a hill above the three rivers, home to the bishops until the 17th century, and the green onion domes of St. Stephan’s Cathedral. As you walk through the cobblestone streets toward those green onion domes, you’ll realize that Passau retains the layout of the medieval town. However, many of the wooden medieval buildings burned to the ground in the 17th century, and the prince-bishops imported Italian artists to build a new cathedral and a magnificent new residence for the bishops themselves. As a result, these splendid structures flaunt Italian baroque and rococo style and ornamentation, complete with opulent gilding and wonderful frescoes.

Your guide will introduce you to some of the architectural highlights—the rococo stairways of the New Residence; the cathedral; and the Town Hall, which boasts a magnificent atrium adorned by large paintings by Ferdinand Wagner—and make sure you get a close-up view of the point where the three rivers meet. But one of the highlights will be aural: Settle into a pew beneath St. Stephan’s exquisite frescoes and listen to the largest organ in Europe fill the cathedral with glorious music.

Note: The organ concert is only available from May 1 to October 31, excluding Sundays and Catholic holidays. An alternative venue will be organized before and after these dates.

The Inn River rises in the Alps, near Innsbruck (hence the name of the famous Swiss ski resort) and flows through three nations (Switzerland, Austria and Germany) on its way to Passau, where it joins the Danube. While the Danube bike path may be Europe’s best-known route for bicyclists, the Inn River bike path, which follows the river from Innsbruck to Passau, has plenty of fans. The route through the Inn River valley outside Passau is an especially attractive stretch, with great views of the lovely countryside, picturesque villages and the sparkling clear river itself. Your guide will make sure you know the local traffic and safety rules before you and your group set out along the mostly flat and paved path, and he will also make sure you have time to appreciate the sight of the three rivers—the Inn, the Ilz and the Danube—merging in Passau. You’ll be traveling on both sides of the river, crossing between Germany and Austria as you cross the Inn, and your journey will include a stop for a typical Bavarian snack of dark bread, local ham or cheese, and perhaps a glass of wine. All in all, it’s an idyllic way to enjoy the scenery and get some exercise at the same time.

Put on your hiking boots, grab a windbreaker and a bottle of water, and head out with a local hiking guide and nature expert to explore the banks of the Ilz River. This small but rushing tributary of the Danube originates deep in the Bavarian Forest, near the Czech border, and is just 40 miles (65 kilometers) long. Its upper stretch is a premier whitewater rafting location, but you’ll be hiking along the lower, serene end of the river. Your starting point is Hals-Hochstein, where you’ll pick up a nature trail that follows a curve of the river and then climbs a steep hill, where you have a great view of the river and woodlands. You will cross the river repeatedly, once by way of a dam and again toward the end of your four-mile (6.5-kilometer) hike, as you loop back to the Hals.

A 900-year-old fortress stands staunchly above Salzburg’s historic center, but the city is much better known for its musical heritage than it is for any military activities. Mozart was born here, performed in public for the first time (at the age of five) here and composed his first pieces here. Salzburg celebrates its most famous son in many forms: with statues, chocolates and festivals—but there are other musical associations to discover too. Walk with your guide through the Mirabell Gardens, the beautiful formal gardens where Maria sang “Do-Re-Mi” with her young charges in the movie The Sound of Music, and admire Mirabell Castle, built in 1606 by Archbishop Wolf Dietrich von Raitenau for his mistress. The archbishop’s official residence, however, lies on the other side of the river, near the cathedral. You’ll ramble through the UNESCO-designated Old Town, where narrow lanes branch off your route, tempting you to explore the shops and cafés that line them, and cross the bridge for a look at the great 17th-century cathedral and the splendid episcopal residence. (Mozart worked for the archbishop of his day—whom he despised— before he moved to Vienna.) It’s part of a group of churches and priestly residences that are linked by arcades that you may wish to check out after your tour.

Note: Lunch is not offered with the full-day excursion to Salzburg.

Linz’s New Cathedral dates to the 19th century (the old cathedral, a few blocks away, was built in the baroque era), but as you take in its neo-Gothic splendor, you might guess that it is much older—until you notice that the stained-glass windows include 19th-century Linz notables. Linz’s new opera house, however, is quite new: It opened in 2013. Covering several city blocks, the Terry Pawson– designed complex incorporates state-of-the-art backstage workshops and staging equipment, which your guide will show you. In explaining why Linz undertook this incredibly ambitious and expensive project, the governor of Upper Austria said, “Culture costs, but the absence of culture costs much, much more.”

You may be ready for a break after your tour, and where better to take one than at Jindrak, a beloved local bakery famous for its Linzer torte?

Refreshed, you will head for the hills—literally. A motorcoach will carry you into Mostviertel, Lower Austria’s famous cider region, where the road winds among beautiful orchard-covered hills and verdant meadows. Tour a typical farm for an insightful look at rural life and local crops, and enjoy the fruit of these orchards—pear and apple ciders—over a delicious lunch of foods produced on the farm.

Crusaders planted the first saffron crocuses in the Wachau Valley at the end of the 12th century, making saffron a valued crop for 700 years—but it disappeared from the terraced hillsides early in the 20th century. It wasn’t until 2007 that an ecologist found mention of it in an 18th-century document at Melk Abbey’s celebrated library. Bernard Kaar, who spent years researching the history of saffron and still more years cultivating the world’s only bio-dynamically certified saffron, is one of the Wachau’s most important producers. Meet Bernard and his wife, Alexandra, for a fascinating introduction to saffron—the plant, the spice and the cultural traditions— and educate your taste buds with flavorful delicacies as you taste red-wine-and-saffron chocolate and saffron-seasoned jams, vinegars and honey. Once you are ready to depart, your host will walk with you to Dürnstein’s Kremser Gate, which dates to the 15th century, and point out the path to the ruined castle above the town, where Richard the Lionheart was famously imprisoned. You can hike up to the ruins or continue to stroll through the charming village, past the blue baroque tower of the abbey church and the picturesque 16th-, 17th- and 18th-century houses.

The Babenbergs, a great medieval ducal family that controlled a wide swath of Austria before yielding to the Habsburgs, were the first to erect a castle on the hill above Melk, which they subsequently gave to Benedictine monks. These monks, some 900 years ago, turned it into a fortified abbey—and the greatest center of learning in Central Europe. Their library was celebrated far and wide (and still is; Umberto Eco paid tribute to it in his best-selling novel The Name of the Rose). Medieval monks there created more than 1,200 manuscripts, sometimes spending an entire lifetime hand-lettering a single volume. Today the library contains some 100,000 volumes, among them more than 80,000 works printed before 1800. This beautiful complex, completely redone in the early 18th century, is a wonderful example of baroque art and architecture, and the views from its terrace are spectacular. As you walk through the abbey’s Marble Hall with your guide, look up at the ceiling fresco painted by Paul Troger: Those classical gods and goddesses represent Holy Roman Emperor Charles VI, allegorically bringing his people from dark to light and demonstrating the link he claimed to the original Roman Empire.

After your tour of the abbey, you’ll have time to explore Melk on your own, or you can take the motorcoach back to the ship.

Ring Street, the great horseshoe-shaped boulevard lined with many of the city’s major landmarks—Parliament, City Hall, the Vienna State Opera, glorious palaces and museums—is a mere 150 years old, practically an infant for a city of Vienna’s age. It replaced the walls and fortifications that had protected the city for centuries. Its construction was a testament to confidence, forward-thinking and grand urban planning, and it resulted in a 50-year building spree. You’ll pass most of these opulent landmarks on your way to the older section of the city, the area the walls once enclosed.

Year after year, it’s ranked as one of the most livable cities in the world. Experience Vienna as the Viennese do and you will quickly see why—it’s not just because of its beautiful architecture, peerless cultural institutions and epic history. Vienna’s a walkable city, but its public transportation is still excellent. The pleasant parks and open spaces invite outdoor activities. Its cozy coffee houses are the stuff of legend, and so are its pastries and sausage stands. Join an expert local guide for a taste of life as the Viennese live it. Walk along Ring Street, past many of Vienna’s landmark buildings: the Museum of Applied Arts, the baroque-era St. Charles Church, Musikverein (home of the Vienna Philharmonic), the Hofburg, Parliament and City Hall, on your way to Volksgarten, Vienna’s first public park (thanks to Napoleon, who blew up the bastion that had occupied the location), with its roses and fountains. Stroll along the neighboring streets, then take a break at a coffeehouse for a typical Viennese coffee.

After your break, wander through the narrow lanes of Haarhoff, pausing in Jewish Square, with its tribute to the Austrian Jews who died during the Holocaust, before wending your way to Vienna’s oldest square, Hoher Markt, where one of the city’s quirkiest sights awaits you: At noon a Vienna Secession (as the art nouveau movement was known in Austria) clock features a parade of 12 historical figures, ranging from Marcus Aurelius to Joseph Haydn, marking the hour. While you wait for the clock show to begin, sample a classic Viennese treat, sausage, from a nearby stand. The adventure ends with yet another very typical Viennese activity—taking the subway.

Experience the sort of entertainment Empress Maria Theresa once enjoyed herself with a private concert of classical music performed by chamber musicians in an exquisite Viennese palace. The music, of course, is by Mozart—but because this is Vienna, it is also by Strauss, and the perfect acoustics in the elegant hall will let you hear their music as if for the first time. Adding to your enjoyment: Beautifully costumed ballroom dancers bring the waltz to graceful life.

Here’s a fun way to see Vienna: Head to Prater Park. Tweens and teens can zoom around the park on Segways, but there’s plenty for younger travelers to do too, including a ride on the Giant Ferris Wheel, built more than a century ago. Unlike American Ferris wheels, which have open seats, the carriages of the Riesenrad resemble miniature railroad cars. It’s one of the tallest wheels in the world, so you get a fabulous view of the city from the top. Back on the ground, you’ll encounter some mouthwatering classic Viennese sweets—because Vienna loves sweets!—by watching the famous Sacher torte being made at Café Demel, one of the city’s most elegant cafés, and sampling yummy Lilliput chocolates at a shop near St. Stephen’s Cathedral. Younger travelers can get a taste of Habsburg splendor at Schönbrunn Palace. At the Children’s Museum in the palace, girls may dress up in the ruffles and brocades of long ago, and boys can don imperial uniforms. Try on tricorns and powdered wigs, flirt with your fan, figure out how to set the table for an imperial banquet—it’s all fun, but it’s also a glimpse into a long-ago world of protocol and grandeur.

St. Martin’s Cathedral gives you a hint of the impressive history of this surprising city. The Gothic church was built into the medieval city’s fortifications; 19 Habsburg rulers were crowned inside it, including Empress Maria Theresa. That’s because Bratislava, then known as Pressburg, became the capital of Hungary after the Ottomans conquered Budapest in 1536, a status it retained until the middle of the 19th century. Close to the cathedral you’ll find St. Michael’s Gate, the last remaining portal of the medieval wall—and your entryway into Bratislava’s Old Town, which blends Gothic, baroque and art deco structures with some less graceful reminders of the Communist era. The stately 18th-century Primatial Palace, in the center of Old Town, was the site where the Pressburg peace treaty was signed in 1805, in which Austria ceded a great deal of territory to Napoleon. Another 18th-century palace, Grassalkovich, is now home to the president of Slovakia. Take some time after the tour to browse through the attractive shops in the lovely art deco buildings that line the squares; you can find a wide selection of traditional folk items at the ULUV (Slovak Folk Culture) shop. And you’ll definitely want to sample some of the local delicacies.

This panoramic tour is a wonderful way to get an overview of the city if you have never been here before. It will carry you from Heroes’ Square, created in 1896 to honor the thousand-year anniversary of Hungary’s founding and its greatest historical figures, past some of the city’s most striking architectural sights—Dohány Street Synagogue, the Hungarian National Museum, the state opera house, St. Stephen’s Basilica and the truly stunning Parliament Building—to Castle Hill, which has been called the heart of the nation. The city of Buda began here, when King Béla built a strong keep in 1243 as a defense against Mongol invaders; a castle replaced the simple fortress, and over the centuries other castles replaced that one. The current castle is primarily 18th century; a museum dedicated to Budapest’s archaeological finds is housed there, and the Castle Hill district has been designated a UNESCO World Heritage Site. You’ll go inside the magnificent 700-year-old Matthias Church, named for one of Hungary’s greatest kings, and then wend your way on foot to the picturesque Fisherman’s Bastion, whose seven fairytale-like towers represent the seven tribes that originally settled the region. It offers a glorious view of the city and the Danube below.

Note: Visits to the interior of the Matthias Church may not be possible on some weekends and Catholic holidays.

Get ready for a fun immersion in the daily life of Budapest— your local guide will show you how to use the metro (one of the oldest in Europe) to easily reach all the city has to offer. Start with a visit to one of the city’s irresistible market halls. Stalls spill over with produce, sausages and meats, festoons of dried paprika, cheeses and jars of honey, all of it authentically Hungarian. After you leave the market, stop for coffee and a sweet treat at Szamos Gourmet Palace, a combination pastry shop, café and chocolate maker in Vörösmarty Square. Marzipan is a favorite confection in Budapest, and Szamos has specialized in making it since the 1930s, so you might want to try some—but the shop’s truffle selection is equally irresistible. Refreshed, you’ll be ready to hop back on the tram for a visit to the gracious green spaces of Károlyi Garden, sometimes described as Budapest’s most charming small park. You’ll ramble along the boulevards and pass the Hungarian National Museum, truly getting the feel for this dynamic city, as you head back toward the ship.

Only the Netherlands and Denmark have a higher proportion of people who use bicycles for their daily transportation than Hungary, and you can spot the bright-green bikes that are part of the city’s bike-sharing program anywhere. Join an expert local guide to experience another side of green Budapest—the side that’s full of beautiful gardens and open green spaces. Wheel along both sides of the Danube, passing the Hungarian Parliament building, and swoop over the bridge to Margaret Island, the narrow strip of land sometimes called the green heart of the city. There are a few buildings on the island but it is primarily parkland. Check out the refurbished Japanese Garden with its musical fountain (the melody it plays is based on medieval Hungarian folk tunes), the art nouveau Water Tower, the petting zoo and the lovely rose garden.

What’s a park without a picnic? Sit down beside the ruins of the 13th-century church (the island was named for a king’s daughter who became a nun here) for a glass of local wine and some typical Hungarian nibbles such as sausages and cheeses. On the other side of the Danube, you’ll stop at the Castle Bazaar, a handsome neo- Renaissance promenade that links the river to Castle Hill, and swing by the legendary art nouveau Gellert Baths before returning to the ship. It’s a fun and active way to get out and see the city the way locals see it.

Imagine living underneath Budapest for 34 years in a secret abandoned hospital. That’s what one couple did, tending miles of echoing caverns lined with ghostly hospital beds, boxes of files, gas masks . . . gas masks? Yes, gas masks. The Hospital in the Rock began as a hospital during WWII, when Budapest was besieged, but it became a secret nuclear bomb shelter—and hospital/torture chamber for prisoners—during the Soviet era in the 1950s. It was so secret that once it was abandoned in 1970, a single couple continued to live here as caretakers, telling no one what they did. Explore these once-secret caves, seeing 70-year-old hospital equipment still in place, along with some 200 wax figures that stand in for the real people who worked on this site of heroism and horror. Why was this place such a dark secret for so many decades? Can you help unravel its mysteries?