This curious fresh and salt water lake holds a secret that draws in deep divers from around the world.

The abandoned medieval theme park was meant to be the "Disneyland of the Philippines."

This wondrous waterfall rushing down a green-covered mountain wasn't discovered until 2010.

An eatery in a shallow river where diners can enjoy their meal mere feet from the base of an artificial waterfall.

A magically clear, blue river that seems to spring from nowhere.

This former coal mine has been turned into a sprawling modern art complex.

Asia's largest limestone cave is home to a world of plastic goblins and gold mining history.

The longest continuous lava tube in the continental U.S. offers 2.5 miles of dark explorations for the adventurous.

Hide from the tourist hordes in these relatively unknown, and unguarded lava caves.

This industrial area was the dumping ground for massive amounts of trash, some of which washes up as tiny bits of sea glass.

A controversial memorial at the place where Captain Cook met his violent end.

This magnificent abandoned hotel has long been haunted by its Nazi past.

A small but industrious mining operation that allows visitors to touch precious gems while they are still in the rock.

The world's smallest movie theater runs on solar power—an attraction in itself.

One of the few surviving street funiculars in the world.

A Milanese café entirely designed by the American director Wes Anderson.

A subterranean shelter remains intact under a busy Paris railway station.

The scars of World War II are preserved on its walls.

This oddly beautiful water cistern is a techno-temple to the wet stuff and a multimedia masterpiece.

A striking public sculpture representing the period of martial law in Communist Poland.

Gliwice Radio Tower, likely the tallest wooden structure in the world.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

A memorial to the beloved brown bear that served in the Polish army during World War II.

There are thousands of tributes and memorials to the King, but none quite like this one in a Kraków city park.