Daily jousts and dancing barrel makers in Munich's mechanical clock.

These pretty kitties killed and ate as many as 135 railway workers.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

A downtown park built on top of unclaimed graves.

Home to items never before seen by the public.

Air Force Academy Chapel made of 100 identical tetrahedrons works to inspire those of all religions.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

The clock that sets them all.

New fungal and bacterial species call this deadly lake home.

The first declared National Monument in the United States.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

When flour explodes, it's not a pretty sight.

The only arched bridge made of stone on the entire Mississippi River.

Scenic mount trashmore, Virginia Beach's most curious waterfront still has a couple of secrets.

A massive sea stack famous for its appearance in The Goonies.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

The magic's in the hole!

Portlandia is the second-largest copper repoussé statue in the United States.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Golden Gate Park's historic collection of plants.

Scattered throughout London are ancient remnants of the city's former bounding wall.

When ecosystems collide in the arid Southwest.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

An enormous, inside-out glass globe built in 1935.