A 19th-century artistocrat's mansion, turned into a library, hidden in a modern library.

For six months of the year, three giant mirrors direct a pool of sunshine onto this otherwise occluded town.

A 200-year-old bar in the historic French Quarter refuses to give up its place in history, nor its role in securing ours.

You can explore the halls of tombs in the abandoned former capital of the Zapotecs.

This exquisite example of early colonial architecture remains unfinished almost 500 years after construction began.

Previously a hot spring, this park remains a site of unique history, wildlife, and geology.

Once thought to be the oldest living tree in the world, Methuselah was germinated before the Egyptian pyramids were built.

Red sandstone structures dominate this landscape, which has been inhabited for some 5,000 years.

Inside this striking glass building, visitors can see thousands of dinosaur fossils in the positions that nature deposited them more than 150 million years ago.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

Only intact Ichthyosaur skeleton in the United States and an abandoned gold mine and ghost town all in one place!

A living snapshot of a different time in America is preserved and maintained by a community of volunteers.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

A bizarre house filled with an astounding array of collections.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

The curiosities and wonders of pharmacy in a delightful historic building.

A pink cottage covered in hearts served as a haven and a resting place for LGBTQ activists.

Once home to an aristocratic family and a workers' organization, this intricately tiled building now houses a chain restaurant.

A striking depiction of Teotihuacan's mysterious "Spider Woman."

The striking jade death mask of an ancient Maya king is displayed in a replica tomb in Mexico City.

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

Islanders once used this dramatic, otherworldly landscape to hide their cattle from Viking raiders.

This strange sculpture of a menacing skull surrounded by sun rays was discovered at the foot of the Pyramid of the Sun.

A castle in the Scottish Highlands has been continuously inhabited since the 1300s.