This astronomical clock is the second oldest in England.

The oldest residential street in Europe also features an optical illusion.

This once-forgotten oasis in the middle of Lisbon was first created over a century ago quite by accident.

An engineering wonder at Pillnitz Castle protects a precious 230-year-old flowering shrub.

This floating garden in the sky is straight out of a fairy tale, but the real thing is nothing short of magical.

Legend has it that this bronze orb, which sat atop an ancient Egyptian obelisk, once held the ashes of Julius Caesar.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

This ancient market is often referred to as the oldest shopping mall in the world.

There's an exclusive Beefeaters pub hidden in the Tower of London.

The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

Where the legendary Orson Welles got his theatrical start before "Citizen Kane."

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

An ancient burial ground believed to have been used for ritual sacrifice.

A grandiose octagonal home crowned by a large dome stands out among the antebellum mansions.

This racially troublesome eatery thought a new coat of paint could erase its offensive connotations.

This monument to the victims of a tragic explosion is said to turn and look at passing cars.

Florence’s mother built a stairway down to her daughter’s coffin so she could comfort her during storms.

The deadly but beautiful ornamental oleander was planted all over the island of Galveston after the hurricane of 1900.

This beautiful Miami garden was designed as a laboratory for tropical plants.

Acres of natural wonders left behind by a socialite-turned-gardener.

This enormous secondhand bookstore inside a Victorian train station sparked the "Keep Calm and Carry On" craze.

The sign at the garden gate reads: "These Plants Can Kill."

This iconic 1,000-year-old medieval castle is a favorite of the film industry, most notably as the location for Hogwarts in Harry Potter.

This giant wooden treehouse within a sprawling garden has its own eatery.