A massive underwater sinkhole made famous by Jacques Cousteau.

Descend 2,030 years into the past in an ancient tunnel built to support Jerusalem's most famous wall.

The bluer than blue waters in these natural Israeli caves are reached via the world's steepest cable car.

These numerous Israeli caves were dug out over hundreds years for reasons ranging from hideouts to burial sites.

One of its engravings is believed to be among the first representations of medical and surgical instruments.

An ancient city exhumed from the depths of the ocean.

One of the most well-preserved temples of ancient Egypt.

A massive work of modern art that appears to be a crop circle in the middle of the desert.

An alien landscape of chalk-rock in the Egyptian desert.

Ozymandias’ time-keeping temple.

An endless sea of white conical domes.

This Bogotá museum houses the world's largest collection of pre-Columbian gold relics.

An unusual and beautiful form of mass transit serves the city's steepest neighborhoods.

The world's tallest palm trees look like the whimsical kind of plant you'd find in a Dr. Seuss story.

Cathedral carved out of salt, located a mile below the earth's surface.

This elegant Colombian fortress was one of the torture headquarters for the Spanish Inquisition.

Colorful lights and mirror-like brine pools create trippy illusions within the historic mine.

Unparalleled stargazing, one of Colombia's best observatories, and a swimming pool can all be found in the middle of this ancient tropical forest.

The caldera of this mini-volcano has been turned into a naturally heated mud bath.

The Andean town where every single building is decorated with a brightly colored frieze.

A dangling church built over a Colombian gorge.

This bone-filled cave got its name after they found 140 bear skeletons inside.

No one knows who built this strange cave of worship or exactly why.

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