27. Cascate del Mulino, Saturnia, Tuscany, Italy
Steaming hot spring water comes out of the ground at 37.5 C and cascades over a series of small waterfalls into dozens of pools on consecutive levels. Niagara Falls it ain't, but the cascading thermal springs at Saturnia are a lot of fun. Soak in the natural sulfurous mineral water and just maybe cure ailments from rheumatism to muscle ache.
About 10 kilometers north of the small Tuscan town of Manciano, northeast of Orbetello. www.cascate-del-mulino.info/en
28. William Bay, Western Australia
A five-hour drive south of Perth, William Bay in Denmark has turquoise waters that lap around white sands and the Elephant Rocks, which shelter an area of rock pools and granite terraces called Green's Pool. The calm waters are perfect for snorkeling, while the more adventurous have the Great Southern Ocean on the other side.
Fifteen kilometers west of Denmark. www.westernaustralia.com
29. Jeju Island Lava Tubes, South Korea
This volcanic island in Korea -- it's on the UNESCO World Heritage Site list -- has mountains, stunning coastal rock formations and the finest system of cave lava tubes in the world. The Jeju caves have towers of petrified lava, while the Cheju-do cliffs have tube-like formations similar to the Giant's Causeway in Northern Ireland.
Jeju Island is 130 kilometers off the southern coast of South Korea. It's accessible by boat from Busan or air from Gimpo airport in Seoul. visitkorea.or.kr
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30. Angel Falls, Venezuela
The highest waterfall in the world, the water at Angel Falls travels 979 meters, which includes a free fall drop of 807 meters. It cascades over one of the biggest table-top mountains in the Canaima National Park in southern Venezuela, known to the local Pemon people as Devil's Mountain. Most of the water evaporates as mist before reaching the bottom.
Angel Falls is in remote jungle near the Canaima airstrip, which can be reached by plane from Ciudad Guayana or Ciudad Bolivar. Local Pemon people work as guides. www.angel-falls.com
31. Lauterbrunnen Valley, Switzerland
Deep in the Swiss Alps the Lauterbrunnen Valley, or Lauterbrunnental, is a deep cleft cut in the topography running between steep limestone precipices. The waterfalls that dot the rift often disappear into wisps of spray before hitting bottom, and include Staubbach Falls, one of Europe’s highest unbroken waterfalls at 270 meters.
Get to Lauterbrunnen, the village in the valley, by narrow-gauge train from Interlaken Ost station in the Bernese Highlands. www.myswitzerland.com
32. Cliffs of Moher, Ireland
South of the village of Doolin in County Clare, the Cliffs of Moher rise 213 meters above the Atlantic Ocean and stretch for eight kilometers. They are one of Ireland's biggest natural tourist attractions, but they also attract Atlantic puffins, razorbills and other wild birds.
Don't miss the spectacular views of the Arran Islands, Galway Bay and the Burren.
Fee: €6 (US$8) per person for access to the visitor center including some pathways.
The Cliffs of Moher are an 80-kilometer drive southwest of Galway. www.cliffsofmoher.ie
33. Skaftafell National Park, Iceland
Formed over millions of years by volcanic eruptions, rivers and glaciers, the Skaftafell National Park in southern Iceland has a variety of striking landscapes. These include an overhanging wall of geometric black basalt rocks on the Svartifoss waterfall, which inspired the architecture of Reykjavik's National Theatre, and the majestic Skaftafellsjökull glacier that seems to have frozen in mid-flow. Drive Road 1 for 326 kilometers east of Reykjavik. Buses from Reykjavik run to the park in summer. www.vatnajokulsthjodgardur.is. Self-guided hikes of Skaftafell are outlined on the official website. www.vatnajokulsthjodgardur.is
34. Lake Titicaca, Bolivia/Peru
At an altitude of 3,811 meters above sea level, Lake Titicaca is one of the largest lakes in South America by volume. It is also the highest commercially navigated lake in the world and is home to indigenous people including the Aymara and the Quechua. Its vast expanse of water is often cloaked in light mist and has inspired numerous local legends.
Lake Titicaca can be visited from the Peruvian town of Puno or from Copacabana on the Bolivian side, 150 kilometers from La Paz. www.laketiticaca.org
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35. Wadden Sea, Germany and the Netherlands
UNESCO describes the Wadden Sea as “the largest unbroken system of intertidal sand and mud flats in the world.” In other words, it's a surreal hinterland along the coast of Germany and the Netherlands that combines wide-open stretches of sand and shallow seas. It’s also home to migratory birds. Go there and you'll feel a million miles from anywhere else on earth and about as small as one of the clams at your feet.
This 600-kilometer stretch of coast lies between the towns of Den Helder in the Netherlands and Niebüll in Germany. www.waddensea-worldheritage.org
36. Puerto Princesa Subterranean River, Palawan, Philippines
Nominated as one of the New 7 Wonders of Nature, the Puerto Princesa Subterranean River runs for 8.2 kilometers underground and boasts limestone karst formations, stalactites and stalagmites. You can cruise down the river in a canoe. Watch out for the Palawan stink badger, an adorable little skunk that lives in the area.
Fee: General entrance fee of P50-75 (US$1.10-1.70) and another cave entrance fee of P200 (US$4.50) for 20-59 year olds.
The underground river is 76 kilometers northwest of Puerto Princesa city on the western coast of Palawan. www.puerto-undergroundriver.com