There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

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

This innocent-looking townhome is actually a subway exit.

An unassuming secret door once led to a legendary watering hole.

A metal ring in the middle of the road marks the exact spot where the Soviet satellite crash-landed in 1962.

An ice field known for harboring an infamous Martian meteorite turned out to contain the oldest air on Earth.

This outpost of America's most popular fast-food restaurant is housed inside a palatial mansion.

A top secret Cold War bunker hidden beneath a Latvian spa facility is now open for tours.

Worship at the altar of seafood at this fish-and-chip shop housed inside the town's oldest stone church.