This amazing example of Valencian Art Nouveau looks more like a cathedral than a public market.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

A series of three shiny letters mark the boundary of an old refuge for those being pursued by debt collectors.

The most loyal of little dogs, or a Victorian era publicity stunt?

A six-ton wedding present for the King of the Scots.

This cannonball embedded in the side of an Edinburgh house once served a surprisingly pedestrian purpose.

A remarkable feat of Victorian engineering across the Firth of Forth.

These ruins saw a second life as a cemetery.

The commemorative stone column conceals a secret laboratory.

The Great Fire of London and the regulation of one-way streets both started in this alley.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

Graffiti from the 16th and 17th centuries cover the walls of this part of the Tower of London.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

An architectural oddity hides in plain sight on this iconic London bridge.

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

This cathedral's stained-glass patchwork of psychedelic colors and shapes was put in place long before the swinging 60s.

The oldest working mechanical clock in the world.

Famously misunderstood wonder of the ancient world

This picturesque horseshoe weir was first built in the 1600s to prevent flooding in the town of Bath.

Recently restored menagerie of Victorian-era beasts.

Iceland's largest geothermal mud pool is a little bit haunted and a little bit dangerous.

This five-foot-tall bronze bird is a memorial to a species that was hunted out of existence.

Medicinal spa created from the mineral-rich runoff of a geothermal power plant