Mysterious 500-year-old tapestries depict a unicorn hunt.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

A museum dedicated to the Spanish occult in a town that was terrorized by the Inquisition.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

Created by one of England's most prolific labyrinth designers, inspired by Bath city history.

The Bristol Camera Obscura housed in an ancient windmill.

This memorial to World War II's fallen airmen shows us the movements of the stars that once guided them.

Semaphore saints, a golden dragon's head, and a stone carved with religious warnings all call this cathedral home.

An incredibly well-preserved piece of ninth-century Viking poop.

This innovative steam machine was no doubt the most famous of the pioneer locomotives.

The National Railway Museum in York is the largest railway museum in the world, attracting almost 1 million visitors per year.

A breathtaking flower tunnel bursts with beautiful golden blossoms.

The world's largest prehistoric copper mine had 30,000 animal bones scattered throughout the maze of passageways.

One of the few surviving street funiculars in the world.

Remnants of the 16th-century defensive wall still stand unassumingly within Edinburgh.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.