A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

A slice of central Asia in the middle of Berlin.

World's first "penitentiary," meant to be humane, drove men insane.

A layered tribute to the work of mosaicist Isaiah Zagar.

Designed by Buckminster Fuller, this relic of the 67 Expo survived fire and ice.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

Week-long block party becomes a competition for the best decorated street.

Large enough to house an internal gift shop.

The King is honored by an elaborate grotto on a continent he never visited.

The colony of South Australia was proclaimed on a hot December day under a distinctively arched gum tree.

Honoring the annual National Cherry Festival.

This pair of Australian "waterfalls" appear to be falling straight across the land.

When you get to Magnetic Hill park near the sign, put your vehicle in neutral gear, and watch it roll uphill...

Nine limestone rock stacks on Australia's "Shipwreck Coast."

Woven tree art gives this towering Australian woodland a touch of mystical whimsy.

One of the best beaches in the entire world.

A clear example of the process of erosion in action.

Australian Lake set aglow by Noctiluca Scintillans.

An Australian lake whose pink hue defies scientific explanation.

Italian cave with exceptional acoustics and an unsavory history.

The world's most active stratovolcano is almost always erupting.

A sprawling Baroque park with 300-year-old hydro-pneumatic waterworks.