The ghostly remains of an accidental sea.

These biodiverse university gardens form a green oasis amid the urban chaos of Mexico City.

This incredible college library is a visual masterpiece of mosaic art. It also looks kind of like a giant boombox.

The largest of only eight working transporter bridges left in the world.

This beautiful deer park was built so King Charles I and his court could go hunting while escaping a deadly plague outbreak.

More than a million titles fill the labyrinthine shelves of this prestigious private library.

Murals of the wild parties once held on the frozen River Thames.

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

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

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

It is still illegal to "quarrel" at this unlikely urban oasis built on top of an electrical substation.