This taxidermy horse was a Civil War hero.

Perhaps the most scandalous statue of America's first president.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

The grand marble structure next to the White House is Andrew Carnegie's temple to Pan-American diplomacy.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

The innocent intentions of this monument are somewhat lost in the sculpture's muscled imagery.

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.

D.C. once had its own tiny rival to the New York Stock Exchange.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

A brass and marble scale model of the solar system embedded in the concrete.

This apartment building designed by a notable Washington D.C. architect housed the Qing Dynasty's Legation.

The final residence of an educator, civil rights leader, and presidential advisor was also the first headquarters of the National Council of Negro Women.

Also known as the Founding Church of Scientology.

The sculptor was instructed to add “stallion attributes” to the general's bronze mare.

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

The historic home of an educator, abolitionist, activist, and poet.

This restaurant has been a haven for D.C.'s LGBTQ community since the 1950s.

Obscure Freemasons still live in D.C.’s largest private residence.

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

These unusual rooms on wheels are holdovers from the 1960s.

In 1998, Larry Page and Sergey Brin briefly ran their fledgling company from this Silicon Valley garage.