Visitors dip into a variety of pools of what was once ice.

A curious whirlpool formation supposedly capable of entangling or engulfing branches, tree trunks, or whole rafts full of hapless tourists.

The first full-scale tunnel built in America is short but scenic.

This pebble beach is so beautiful that taking its rocks is against the law.

A record-breaking pool that uses computers to turn ocean water into cleaner, private swimming water.

This floating cinema brings new meaning to the phrase "going out" to the movies.

Explore the complex ecology of this multifaceted nature preserve by riverboat.

Vortex-shaped aquarium hosts Europe's largest school of piranhas and other ocean creatures.

Medicinal spa created with the discharge from a geothermal energy plant.

An ethereal glowing blue ocean cave in Croatia.

Millions of glowing microscopic organisms light up the waters of this luminous lagoon.

Home to the infamous "Typhoid Mary" and the worst loss of life in New York's history prior to September 11, 2001.

Geothermal waterfalls in Tuscany.

An eatery in a shallow river where diners can enjoy their meal mere feet from the base of an artificial waterfall.

A series of waterfalls so massive they straddle the border of Argentina and Brazil.

A magically clear, blue river that seems to spring from nowhere.

This crescent-shaped sliver of sand is a magical haven for a herd of feral horses.

Dolphins, ancient clams and hundreds of waterfalls make this one of the world's top tourist destinations.

This neon blue river gets its color from a unique mix of bacteria and volcano minerals.

This small town in the Netherlands has no roads but instead, miles of canals and over 100 bridges.

Two small chapels housed inside an ancient tree.

Site of a former hidden treehouse in New Orleans.

Lavish royal estate punctuated with heated greenhouses.

Started as a kitchen garden, now the second largest botanical garden in the world.