Try not to get slimed in Tribeca.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

A crumbling hospital from the 1850s on Roosevelt Island.

A terrific purveyor of natural history objects and curios.

Inside the world's largest seed bank, WWII botanists elected to starve to death rather than compromise their collection.

This Bordeaux parking garage has 712 indoor spaces, and one outdoor.

The world's largest reflecting pool is just two centimeters deep.

This massive blockhead sculpture hides an entire library.

This abandoned coliseum was intended to be a grand Nazi rallying ground before it was halted at the end of the war.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

An ancient Egyptian temple in the middle of Madrid, Spain.

A somber memorial at the site where hundreds of prisoners and civilians were executed in the aftermath of World War II.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

A sharp sculpture made of thousands of pieces of jagged glass.

An ancient octagonal weather station named for the eight Greek gods of wind.

The ruins of an abandoned medieval city where the last Byzantine emperor was crowned.

Brussels' favorite peeing boy has a sister.

A little sculpture with a large wardrobe.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

Climb inside an iron crystal magnified 165 billion times its normal size.

Cozy basement bar sports an inventory of over 2,000 beers.

It houses the remains of a 17th-century version of the Titanic.

Christ's blood allegedly preserved in a Belgian town.