The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

An abandoned asylum where patients have been forgotten but their possessions remain.

An elevator into the Baltic Sea.

Where manatees are the snowbird vacationers in these balmy Florida springs.

These ruins of a pre-Columbian cliff village are among the most beautiful and well preserved in New Mexico.

A solitary tree has grown up all alone on Lake Wānaka, backdropped by the beautiful Southern Alps.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

Remember that scene in the Matrix, when Neo is in the big white room with all the weapons flying by? Well, this is what it would look like if he had wanted trees instead of guns.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

A museum within a museum, devoted to history's most questionable medical devices.

Hear the quietest sound from across the dome.

360° views of the city plus five floors of optical illusions and hands-on science.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

A submerged village appears when dam levels drop.

Home to the "Circus" trees created by Axel Erlandson.

Eons old volcanic activity created one of the most stunning rock formations in the United States.

These fantastically named natural pools look like something out of a Scottish myth.

One man's extraordinary topiary garden in a small South Carolina town.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

Ruins of a 10th century church tucked away deep in a botanical garden.

The largest stone moai on Rapa Nui.

America's only nuclear missile silo open to the public.

Geothermal waterfalls in Tuscany.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.