Monkeys inhabit the lush forest surrounding ancient Mayan ruins once considered sacred.

Central America's deepest lake is actually a volcanic caldera, surrounded by three volcanoes.

One of the world's largest pyramids stands within El Mirador, the "lost city of the Maya."

One of the world’s most colorful cemeteries, where each pigment is symbolic.

Volcanically heated hot springs.

Hidden deep in the Guatemalan jungle is a turquoise paradise of natural pools, caves, and waterfalls.

An enormous, 30-story-deep hole in the middle of Guatemala City.

Giant kites are flown during this Day of the Dead celebration in Guatemala.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

Bubbling up from deep underground is the warm crystal clear water that fills the Warm Springs Pools, America's oldest spa.

This pre-Revolutionary War grist mill ground corn and flour for soldiers in seven American wars.

The only recreation of William Shakespeare's indoor playhouse.

This beautiful vintage movie palace has seen little change in form or function since the 1920s.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

Formerly the world's largest, this Willy Wonka-esque contraption runs 24/7.

Thousands of artifacts relating to human sexuality, including the world's largest sex bike.

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

The railway carts travelers to central Athens's highest peak, which offers stunning vistas of the city.

Monasteries on rock pillars, once accessible only by frayed ropes.

This Croatian fairytale castle is slowly falling apart thanks to years of neglect.

This truly palatial work of Communist-era architecture now sits crumbling on a Croatian beach.

Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

An ethereal glowing blue ocean cave in Croatia.