This hidden green space is the city's second largest conservatory.

A celebrity from the late Cretaceous period.

This 14th century tower house was once the home of Irish poet W.B. Yeats.

The peaceful space is adorned by paintings by the famed abstract artist Mark Rothko.

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

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

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

This cemetery served as the only official burial grounds in Cambridge for nearly 200 years.

The statue of John Harvard isn't actually John Harvard—or even, technically, the founder of the school.

Once a black market electronics marketplace, now an otaku shopper's paradise.

This 30-foot pile of rocks may be the grave of a mythological Irish queen.

This pump on the bad side of Victorian London betrayed a horrifying revelation about the water supply.

A typical "Old South" manor, once owned by author Anne Rice, served as the setting for several of her witchcraft sagas.

The second oldest continuously operating bar in Louisiana.

This symbolic piece of New Orleans architecture is also home to a few ghastly stories.

A 200-year-old bar in the historic French Quarter refuses to give up its place in history, nor its role in securing ours.

A former major munitions plant that has been converted into a sprawling art space.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

Decades before the scandal, this staircase on the river was a literal "water gate."

A community of artists and entrepreneurs seeks a simpler life on London's waterways.

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

The remains of an ancient Roman teenager are memorialized at the base of a modern London landmark.

Mary Kelly was last seen here before she was murdered by Jack the Ripper.

What happens here stays here – unless it affects the whole world.