This massive swimming pool is the high tech home to the human-powered submarine races.

Exact replica of the ancient monument, but much, much lighter.

These figures float and flutter in this fountain crafted by famed Swedish sculptor Carl Milles.

One of the oldest train stations still standing in Virginia played a vital role during the Civil War.

The most historic church in Fairfax County played a role in the creation of the American Red Cross.

America's post-nuclear-attack chambers of Congress.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

Take a steam-powered ride straight out of the past on this Appalachian rail line.

An overgrown collection of miniature buildings still stand as evidence of one couple's obsession with The King.

One of the last active volcanoes on the Eastern seaboard.

Bubbling up from deep underground is the warm crystal clear water that fills the Warm Springs Pools, America's oldest spa.

The only recreation of William Shakespeare's indoor playhouse.

The oddly shaped, steam-spewing building is now an art studio and gallery.

This historic mansion was built as a symbol of love between a husband and wife.

Hidden for 165 years inside a building designed by Thomas Jefferson are the remains of what may be America's first educational chemistry lab.

Edgar Allan Poe's old dorm is now a shrine to the author's legacy.

Thomas Jefferson's estate is home to hundreds of varieties of historic fruits and vegetables.

Take an otherworldly journey in a school dedicated to out-of-body experiences.

A "hospital" where people went to be quarantined, die, and be buried in the yard.

The flower-shaped temple in Virginia aims to transcend the boundaries of the world’s religions.

The famous abolitionist’s preserved estate is one of Washington's finest monuments to its great Black citizens.

A haunting tribute to pioneering photographer Clover Adams.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

A painfully obvious spy house sits right across the street from the Russian Embassy.