Embark on the Crystal Ravel at the beautiful port of Regensburg.

Situated at the northernmost bend of the Danube and boasting a well-preserved medieval center, charming Regensburg finds itself not only a UNESCO World Heritage Site but also a traveler’s favorite destination. With its 1,400 or so ancient buildings standing as a regal testament to days gone by, this riverside treasure, complete with the elaborate cathedral, quintessential clock tower, multi-arched bridge, and multi-faceted personality, is a flourishing city.

At the confluence of the Danube, Inn and Ilz rivers, Passau is also situated at a meeting of cultures. The town began as a Roman settlement, enjoying the rising tide of influence as the largest bishopric in the Holy Roman Empire and enduringly vibrant as a hub for various trade pursuits, including salt, swords, and ideas. Wander the cobbled streets of Old Town, gaze upon arched bridges and Italianate manses and visit magnificent St. Stephen’s Cathedral and New Bishop’s Residence.

Today, get a chance to cruise the scenic Wachau Valley.

Best known for its fortified baroque Benedictine monastery, Melk Abbey, the town of Melk boasts an assortment of smaller gems. Among them, the city’s riverside location, serene and regal with a ribbon of wooded groves giving way to the lovely village. Cobbled lanes and a petite size make for a pleasant stroll with a chance to discover its 16th-century Town Hall, or Rathaus, in the center of town, and Haus am Stein, or House at the Rock. Built-in the 15th century, the vine-covered abode is Melk’s oldest building.

Considered one of the most visited tourist spots in the Wachau Valley, Durnstein is in a robust wine-growing region sitting alongside the Danube river. Durnstein Castle, the region's famous architectural highlight, sits atop a rocky mountain, high above the Danube, at its base. Durnstein's beauty is enhanced by verdant forests, rolling hills, and thriving vineyards that surround the town. Sip some of the region's local wines and enjoy a leisurely day in this postcard-worthy European town.

Once the capital of the Austro-Hungarian Empire and forever known for its manicured gardens, ornate architecture - especially that of the famed Ringstrasse - and distinguished roster of composers who either were born or lived here, Vienna finds itself at the very center of European culture, even as it sits near the border of the Czech Republic, Slovakia, and Hungary.

Commanding both sides of the Danube – with the Chain Bridge connecting hilly Buda with flat Pest – Hungary’s capital enchants with its magnificent architecture of domes and spires, 18th-century homes, bridges, and lampposts. The UNESCO-listed Castle Hill welcomes all to explore Buda Castle, Trinity Square, Matthias Church, and Fisherman's Bastion.

After breakfast aboard the Crystal Ravel, disembark at the beautiful Budapest.