A priceless collection of the Nation's cryptologic history.

This sacred cavern, 400 feet deep, is home to millions of bats and an ancient burial ground.

Manatees congregate around a power plant's discharge canal where the water is especially warm.

First flying reptile discovered in British Columbia was for years forgotten in a cabinet.

Designed by Maya Lin, the memorial honors 41 individuals who died fighting for equal rights between 1954 and 1968.

Shoreline strewn with the remains of ghostly fallen trees.

See massive fossils that are over 200 million years old in northeastern Arizona.

A museum devoted entirely to hammers has more than 1,400 items on display dating back to the Romans.

World's largest cave was only discovered in 1991, and now offers tours to the public.

Last remaining nuclear missile base in Ukraine.

An ancient stone fortress considered by many to be the eighth wonder of the world.

The only castle in North America to ever house European sovereigns.

The final resting place for the remains of 143 Habsburg royalty.

On the outskirts of a desert trading village high on the Andean plain, steel giants have been destroyed by salt winds.

A community of collapsing homes more than a mile out from the Florida coast.

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

The largest collection of ornamental hair combs on the planet.

Iconic pyramid from famed British architect Norman Foster designed to represent all of the world's religious faiths.

Two thousand artifacts from around the world collected by one woman who loved to travel.

Collapsed television tower finds new life as a control tower for boat races.

Sculpture designed by Turkish artist and professor Mehmet Ali Uysal.

One of the most unusual geological features, recognizable from a dozen hit movies.

Eighteen mummies have stood guard behind the altar of this tiny church since 1833.

This Japanese national treasure was originally built in 593.