This strange geological landscape erupts with sudden bursts of water.

The most southerly spot on New Zealand's South Island is home to surreally shaped, permanently mangled trees.

Known for the tunnel that leads visitors to the water.

A glacier pocked with ice caves and surrounded by rainforests.

This electric green sulphur lake in New Zealand looks like a cartoonish radioactive dump site.

A perfect turquoise lake colored with glacier dust.

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

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

Tubing through a cave lit with glowworms is a magical underground experience.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

The oldest operating apothecary in the US has treated everyone from Thomas Edison to Mark Twain.

A monument celebrating the idea of reaching inaccessible places.

The innocent intentions of this monument are somewhat lost in the sculpture's muscled imagery.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

Look closely and you’ll notice that the color changes a third of the way up the tower.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.