The whole world in one water tank.

Fascinating museum dedicated to the under-appreciated medical history of urology features some wince-inducing devices.

This beautiful stone arch bridge wasn't even expected to stand for one day, but people have been crossing it for centuries.

Brain collection and database that narrows the gap between man and animal.

A remote horde of architectural treasures fit for Indiana Jones.

A remarkable time capsule of American manufacturing deep in Maryland coal country.

A Civil War Museum with some notable medical antiques.

A haunting exhibit in a wildlife refuge center highlights threatened species and the conservation efforts needed to save them.

Captain John Smith thought these cliffs were amazing in 1608 but sharks thought so 20 million years before him.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

An eerie, abandoned military base engulfed by nature and graffiti is now home to a local park.

After hundreds of years of settlement, this once-bustling fishing village sunk into the Chesapeake Bay.

This dig site outside D.C. is known for its exceptionally high density of baby dinosaur fossils and dinosaur eggs.

This abandoned Victorian-style house was built in 1884.

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.

A girls' boarding school inspired by the Chicago World's Fair, once abandoned, now restored to strange and scenic glory.

The ruins of this long-abandoned unsuccessful gold mine can still be found.

The land is home to swimming ponies and a legendary 18th-century treasure.

This English-inspired Maryland garden is home to acres of opulent plant life including bushes shaped into an entire fox hunt.

A priceless collection of the Nation's cryptologic history.

Bizarre Cavern.

An astounding collection of medical specimens, including bits of President Lincoln.

An eerie, decaying ghost town destined to fade into the forest.