Bizarrely shaped rock formations in northwest Bulgaria come with equally bizarre legends.

An architectural marvel that spans the Arda River, and has stories of a haunted past.

An abandoned saucer-shaped monument in the Bulgarian mountains.

1800 rooms of single-family residence in Brunei.

A symbol of Islam in oil-rich Brunei.

Divers can encounter an abandoned warship encircled by a giant kraken submerged in the British Virgin Islands.

A mountain of conch shells created by centuries of fishermen.

This huge pile of volcanic boulders hides a stunning network of secret grottoes.

An abandoned stretch of elevated road in the middle of the Brazilian jungle.

After millennia of erosion by sand and churning water this Brazilian valley now looks like a lunar fantasy.

Part of one of the largest flooded cavities on the planet, and littered with prehistoric animal bones.

Spanning over 10,000 square miles, this ancient salt pan is one of the largest on the planet.

An enchanting rocky island of scraggly baobabs surrounded by an ancient sea and sprawling salt pans.

There is only one place in the world where the corners of four nations come together.

Wondrous stalactites house thousands of bats in these African caves.

This museum preserves the hand-dug tunnel that kept Sarajevo afloat during the Serbian siege.

There's a mini version of Iguazu Falls hidden in the Balkans, and it's got a rope swing.

This cluster of little wooden huts once ground local farmers’ wheat into flour during the days of the Austro-Hungarian Empire.

A desert that evokes the surreal.

Astronomical observatory above Lake Titicaca.

Bolivia's needle-like rock formations.

Largest site of dinosaur footprints ever found includes more than 5,000 tracks.

This red lake 4,000 meters above sea level is home to rare flamingos.

A valley of unique erosion patterns lends to a view like nothing on Earth.