Five miles of underground river link lake to ocean.

It is believed that the historic tower is sinking at a rate of an inch a year, though no one is completely sure why.

This burial cave houses around 100 ancient coffins, neatly stacked to form a massive wall.

Hundreds of wooden coffins dangle from cliffs and caves in the Philippines.

These tiered rice paddies were carved into the hillsides 2,000 years ago.

A church made of steel.

Just off the road outside Baguio, a gigantic lion's head carved into a mountain greets those driving by.

A military museum, art park, mausoleum, and architectural oddity all on one fascist's estate.

This Swiss cemetery is reserved for people who died in climbing accidents.

An architectural marvel that combines Gothic architecture with Indian elements.

The bridge that cost Germany a World Heritage Site.

When the rain falls, this drain system turns into a musical instrument.

This scenic spot is known as the birthplace of Switzerland.

These 20-foot jaw bones honor a time when the leviathan bones were a sign that whalers survived the hunt.

Along a coast that sees the annual migration of humpback whales, a geological formation that takes the shape of a whale’s tail.

Now an entertainment complex, the Lingotto building was once an avant-garde auto factory with a test track on the roof.

One of the oldest and most significant collections of Ancient Egyptian archeology outside of Egypt.

Something's watching you.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

This snug medieval lane is one of the narrowest streets in the world.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.

A muddy alien landscape that is home to rare species of exotic plants.

A lover's walk between hilltop towns, decorated with graffiti love notes.