Hiking Rila's Seven Lakes (Rila, Bulgaria): This moderate 2-day (or more) hike from Rila Monastery into Bulgaria's Alps to view the eerily beautiful Seven Lakes is the most rewarding hike in the country. After the first day (a fairly strenuous 6-hr. hike), you reach the Ivan Vazov hut, which you can use as a base to visit the Seven Lakes. Better still, push on to one of the Sedemte ezera huts on the shores of the lowest lakes. If you can, book the newest, which has the best facilities.
Plitvice Lakes National Park (Croatia): Plitvice is Croatia's best-known natural wonder. You can choose the difficulty of your exploration, from challenging 8-hour hikes to shorter treks eased by ferry and tram rides. The park's 16 crystal-clear turquoise lakes and their countless waterfalls are the marquee attraction, and you'll be fascinated by these pristine ponds, which flow into one another and tumble over deposits of travertine, creating waterfalls that drop a few feet or plunge as much as 64m (210 ft.). All this beauty is set in a dense forest accessed via footpaths, ferries, and fuel-friendly people-movers.
Taking a Slow Boat Down the Vltava (Czech Republic): You can see many striking architectural landmarks from the low-angle and low-stress vantage point of a rowboat you pilot yourself. At night, you can rent a dinghy with lanterns for a very romantic ride.
Riding a Faster Boat Down the Vltava (Czech Republic): For those not willing to test their navigational skills or rowing strength, tour boats offer floating views, many with meals. Be sure to check the float path to be certain your boat travels past the castles and palaces.
Hiking in the Hills Outside Szigliget (Hungary): You can hike up to the fantastic ruins of a 13th-century castle above this scenic village in the Lake Balaton region, or go farther north and hike into hills covered with vineyards.
Swimming in the Thermal Lake at Hévíz (Hungary): Even in the depths of winter, the temperature in Europe's largest thermal lake seldom dips below 85° to 90°F (30°-32°C). Hungarians swim here year-round, and you can, too! If you visit in winter, it'll be a memorable experience.
Hiking in the Tatras (Poland): Zakopane is the jumping-off point to hundreds of kilometers of gorgeous hiking trails. You can choose one of the 2,000m-plus (6,560-ft.) assaults on the peaks, or a more leisurely stroll along breathtaking valleys, carved out by tiny mountain streams.
Idling Through the Backwaters of the Danube Delta (Romania): Considered by some to be Europe's most important wildlife sanctuary, the Danube Delta once was threatened by Communism's unchecked industrial program. Now the Delta once again is a haven for bird life, including its famous pelican population, which you can observe while on a boat safari through this unique ecosystem of waterways, lakes, reed beds, sand dunes, and subtropical forests.
Picnic at Kolomenskoye (Moscow, Russia): This architectural reserve boasts the breathtaking 16th-century Church of the Assumption and the wooden house where Peter the Great sought refuge before assuming Russia's throne. The surrounding lawns beckon visitors to stretch out with caviar or cucumber sandwiches and a thermos of strong Russian tea.
Rafting the Dunajec (Slovakia): This is fun for the whole family. It's not intense white-water rafting, but a gentle group-float down a winding, twisting river that marks the boundary between Poland and Slovakia. The guides are good-natured and bedecked in the traditional folk costumes of the region.
Having the Ride of Your Life (Slovenia): Compact and oozing spectacular scenery, Slovenia may be the ultimate cycling destination. Verdant valleys, dark forests, and rural countryside and hills beckon, but the challenge that your muscles will remember forever is the steep ascent up and over the Vrsic Pass in the Julian Alps; the 50 hairpin bends will exhaust you, but the views along the way will leave you breathless. Of course, it's less tiring by car!
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.