This striking observation tower shaped like a spinnaker sail is the newest icon in historic Portsmouth.

A miniature village mimics the surrounding buildings so well it includes itself.

A lush indoor jungle fills this bustling Madrid transportation hub.

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

The commemorative stone column conceals a secret laboratory.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

Single runway interrupted by a busy road that cuts across its middle.

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

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

The largest timber structure in Europe.

These lamps were created to expel sewer gases after an event known as The Great Stink.

A rather grand, but tiny, folly on the banks of the River Wear associated with a Polish count.

These upturned herring boats make nifty storage sheds for fishing goods.

Twice a day this ancient path disappears with the tides, leaving the Holy Island of Lindisfarne out to sea.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

Dozens of Soviet-era trains and carriages fill this outdoor museum.

Once one of the largest rooms full of books in the world, this bookstore basement is still a treat for bibliophiles.

This library dates back to the late 17th century and was one of the first public lending libraries in England.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

The world's largest wooden structure.

Commonly acknowledged as the only public monument to the Devil himself.

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