This medieval footbridge in the Swiss Alps is known to attract cliff-jumping daredevils.

A centuries old castle atop a dormant volcano houses museums devoted to both women and witches.

The world's oldest grape-producing vine has survived four centuries of turmoil and even has its own anthem.

Double spiral staircases are not unheard of, but they are very rare.

The shell of a medieval fortress offers commanding views of the area it once protected.

An otherworldly alpine pasture with its own unique microculture that recalls Middle Earth.

This one-time health resort was used by aristocrats around the world.

Artfully arranged bones of 5,800 Austrians.

A silly medieval mural preserved on the side of a Viennese house.

Legends surround an ancient tree trunk riddled with nails for good luck.

A glimpse into the festive and private lives of medieval Europe.

Handsomely crafted representations of our round planet.

The oldest hotel in the world has been operated by the same family for over 1,300 years, even catering to samurai.

The final resting place of the world's first nuclear reactor.

The secret city built by the Manhattan Project.

The site of an underground detonation of a megaton nuclear bomb in the middle of the Mojave Desert.

The birthplace of both the Atomic Age and Godzilla, and the namesake of the bathing suit.

"Not too many people can say they've had a nuclear bomb dropped on them, not too many would want to." — Walter Gregg.

An enormous concrete structure built over a nuclear crater.

The largest man-made crater in the U.S. marks the spot where we once tested mining with nukes.

The contents of this safe survived a 37-kiloton nuclear bomb.

This largely forgotten piece of Cold War history stands hidden in the woods just north of the Mississippi Gulf Coast.

On October 26, 1963, a 12-kiloton nuclear device was detonated here in granite some 1,211 feet below the ground surface.

A facility built in 1992 for an underground nuclear test remains in place today.