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

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

A hidden passageway now marks the site of an assassination attempt on Ronald Reagan that some say broke a 140-year-old curse.

You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

Within this beautiful Pittsburgh cemetery, a unique headstone bears witness to one man's eternal love for Jaws.

An imposing pair of sphinxes stand guard outside this Egyptian Revival tomb.

This Old Testament garden features 100 plants from biblical times.

A private residence adorned with a gorgeous mural dedicated to the buzzing insect.

The Master of Magnetism dominates the walls of a scrap metal yard to keep graffiti artists at bay.

With 3,000 bikes on display, the world's largest bicycle museum includes some famous rarities.

One Pittsburgh musician's decades-in-the-making memorabilia collection is on display at this rock-n-roll curio shop.

A beautiful oddities shop crammed with strange and morbid curiosities.

This shop filled with oddities and knick-knacks is named for a 19th-century charlatan.

One of the steepest streets in the United States makes an intriguing challenge for cyclists.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

The John Snow Memorial marks the epicenter of London's 1854 cholera epidemic.

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

This liminal destination combines creaky carnival rides, a classic car museum, and luck-of-the-draw flea market finds surrounded by dust and drive-in movie screens.

Over 50 whirling pools left behind from the glacial age.

Founded by the famed children's book artist, this museum spreads an appreciation of the arts through picture books.

An old trolley bridge was converted into a breathtaking garden bursting with colorful flowers.

This quarter-mile tunnel under the Bluff in Pittsburgh bends at a 45-degree angle.

This residential door allows San Francisco muggles a glimpse at the wizarding world.

Its buzzing collection honors vibrator history.