The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Locals dubbed it the "Owl Building" because of its bird-like appearance.

The final resting place of many of New Jersey's most famous residents, including U.S. history's most in-vogue antagonist, Aaron Burr.

Infamous marsh filled with toxic waste, World War II-era London rubble, and dead mobsters galore.

The boulder on which Alexander Hamilton laid his head as he died can still be visited on the New Jersey coast.

New York City's smallest piece of private property.

This unacceptably tall building was the real reason for Washington, D.C.'s skyscraper ban.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

Look closely and you’ll notice that the color changes a third of the way up the tower.

A line of blue paint marks the route of the inaugural parade.

A water pumping station disguised as a residential home to assuage concerned neighbors now tricks most passersby.

A historic Civil War estate-turned-museum looks back on the Confederate States of America.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

Small teepee-like houses built for TB patients have become sheds, studios, and bus stops around Colorado Springs.

This was once the home of Gahan's Saloon, Denver's most storied speakeasy.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

At this Denver landmark, the meals are compulsory, the sopapillas are complimentary, and the insanity is everywhere.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

An easily overlooked memorial to a Ukrainian famine-genocide that killed over 4 million people.

The tunnel under the Capitol Building where Congress takes out its trash.

After his presidency, George Washington planned to live only a few blocks from the Capitol building.

"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!”

Washington's iconic carousel has a nice piece of Civil Rights history.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.