Death rituals and sacrifice inside a Peruvian megalith.

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

Keshwa chaca, among the last handwoven Incan bridges, crosses Apurimac Canyon in Peru.

A colorful Peruvian city of the dead.

Extraordinary rock formations in open Peruvian fields.

Nazca pilgrimage site covering 370 acres is a popular stop for archeologists and looters.

Peru’s only toy museum houses everything from pre-Inca whistles to lead soldiers and terrifying dolls.

The outside of this exposed Moche pyramid is covered with striking colorful adobe friezes.

After an epic flood washed away its enslavers, this city has been part ghost town, part cultural wildcard for the past three centuries.

A breathtaking 19th-century trail overlooks Lake Tahoe.

This 200-meter-high waterfall marks the site of Achilles’s immortal baptism at the mouth of the River Styx.

A Victorian marvel of engineering is now a 21st-century tourist attraction.

This famed marionette theater and museum is bursting with imaginative string puppets.

This old, abandoned hotel offers magnificent views.

Underneath a chalk hill in France lies what Hitler hoped would be the underground launching base for a devastating new weapon.

Remnants of the Nazis' occupation of Denmark linger along the sand.

Hidden in the forest are the crumbling, graffiti-covered remains of the factory where most of Germany's explosives were produced during World War II.

This bunker in northern France was built by Nazi German forces with the intention of launching up to 50 V2 rockets at London each day.

Approximately 300 million years ago, a massive coral reef existed in what is now the largest limestone cave in Japan.

The walls of these four caverns are filled with art that dates back to the earliest human presence in Europe.

Through the colossal entrance to this cave you'll find limestone tubs and an underground waterfall.

A spectacular Bulgarian cave resembling a devil's head with a waterfall rushing down its throat.

A steep and winding road in the Yorkshire Dales passes by these deep natural potholes.

A long, winding trek rewards you with a gorge so captivating it inspired a painting in the Tate.