This monument to one of the largest science fiction games of all time bears the names of hundreds of thousands of players.

The famed amusement district marks the beginning of summer with a wild procession of nautical creatures.

The iconic Manhattan corner that was once the site of the Beastie Boys' fake clothing store.

Avoid gangster interaction while window-shopping.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

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

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

A miniature rainforest is growing inside of a Midtown Manhattan office building.

A crumbling hospital from the 1850s on Roosevelt Island.

Six neolithic sandstone boulders remaining from a dolmen.

The oldest working Brewery in Britain.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

This 1920s Dutch barge is now a floating bookstore.

The final resting place to 300 Victorian-era pets hides inside the city park.

An incarceration museum on the spot of possibly the oldest prison in England.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

This South London cemetery holds the remains of more than 15,000 people.

A kaleidoscopic warehouse-maze of handmade neon signs.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

A great example of the inventive canal bridges that were deliberately split down the middle.

This mysterious hilltop collection of Druid carvings isn't quite what it seems.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.