Pompeii's less famous neighbor is still revealing her secrets.

A dark tunnel leads to a striking white crater that seems to be from another planet.

Inside this mountain lies several kilometers of breathtaking caves.

If you can look past the nearby sewer pipes, this urban sinkhole grotto is a mini-paradise.

The meteor that sealed the fate of the dinosaurs landed at this site, one of the largest impact craters in the world.

A scientific repository of goiters, boils and other ailments throughout Mexican history.

A hidden treasure of an abandoned city lies deep in the jungles of Campeche, Mexico.

A flooded Mexican cave that hides a river beneath the water.

Two waterfalls flow down the cliff faces decorated with rare natural basalt columns.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

The jewel of western Mexico's archaeological legacy is this tiered circular pyramid now covered in grass.

The ruins of an ancient Mayan city, beautifully preserved and only accessible by boat.

A 500-year-old series of tunnels long believed to be folkloric was uncovered beneath the streets of Puebla.

An ancient system of freshwater caves filled with animal bones, including that of species long-extinct.

The winter home of millions of migrating monarch butterflies.

Visiting this cacophonous collection of vintage novelties is like stepping into the mind of a crazed toymaker.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

The largest cave shaft in the world is home to thousands of birds and popular with BASE jumpers.

Twelve natural mummies are displayed in the crypt of this former monastery school.

This fantastical house shaped like a seashell brings aquatic design to architecture.

An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

A church dedicated to the Mexican skeleton saint.

High atop a Mexican rainforest mountain, this ancient pyramid once drew pilgrims countries away.

Underwater art project will double as a massive artificial coral reef to help regenerate the damaged ecosystem.