America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

This university transit system is a 1970's vision of the future.

In Twickenham sits a small whitewashed castle that inspired Mary Shelley's 'Frankenstein.'

A graveyard that dates back over 200 years stands near a busy shopping center.

Alexander Hamilton’s creation caused quite a bit of controversy.

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

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

The massive, original Colgate Clock is mounted on a defunct factory building that was once a prison.

This candy shop has been serving up sweets to the Louisville area since the 1850s.

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

The pop art icon's gravesite is broadcast 24 hours a day on his museum's website.

A historic arena where the Beatles played their first concert in the U.S.

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

No one knows who created the statues or if they are arranged properly—let alone the artwork's real name.

Frank Lloyd Wright’s most iconic home dangles over a Pennsylvania waterfall.

The United States’s oldest funicular railway glides up and down a steep Pittsburgh street.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

This grand gothic brewery has been pumping out suds for over a hundred years.

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

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

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