The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

Dedicated to improving the plight of the rare scaly anteater.

A battle between nature and architecture in the Cambodian jungle.

This large round boulder is said to emit spiritual power, but it may just be magnets.

One of Chile's most active volcanoes is riddled with beautiful caves.

A fantastical group of cliffside stairways, bridges, and twisting paths carved out of stone provide a surreal coastal hike.

This Japanese-inspired labyrinth of hot springs is hidden in a Chilean forest.

The largest stone moai on Rapa Nui.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

This daunting 1st century fortress was purportedly the site of one of the most dramatic revolts of the Jewish-Roman wars.

A more chill but no less fascinating version of the famous ancient archeological site.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

Northern Ireland's Brobdingnagian stepping stones.

The ruins of an 800-year-old monastery boasts the tallest round tower in Ireland.

This 30-foot pile of rocks may be the grave of a mythological Irish queen.

Local legend says the remains of Father Christmas lie within the medieval grounds.

A standing relief of a Norman knight whose posture marks him as a Crusader.

This single room has survived the centuries with almost no deterioration.

This ancient Irish tower could easily have stood in for Rapunzel's prison.

Huge standing stones mark a site of megalithic mystery.

This controversial Irish show cave is home to a massive formation known as the Great Stalactite.

An Iron Age fort on the edge of a seaside cliff offers a glimpse into an ancient, mystical world.

This singular Irish dolmen is more Frank Lloyd Wright than upright stonehenge.

There might not be much left of these Irish ruins, but their linguistic legacy is still going strong.