An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

A replica of the steam engine that hauled Queen Victoria's Royal Train is on display at Windsor.

Overlooked by many, the two famous Scottish warriors guard the main gate of Edinburgh Castle.

Don't be fooled by this fake medieval facade even if it is almost 300 years old.

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

The final resting place of soldiers' loyal canine companions.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

Famously misunderstood wonder of the ancient world

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

These fantastically named natural pools look like something out of a Scottish myth.

An Irish town has built a statue to a silent film actor simply thanks to the holidays he once spent there.

A proud bronze billy stands as an eternal symbol of Ireland's oldest festival, where a goat is made king.

A hugely vast Irish landscape of barren rock that stretches for miles.

An ancient neolithic tomb that only sees the sun twice a year.

The ancient tomb acts as a calendar that keeps perfect time.

This bridge was constructed from the rubble of the infamous Bastille.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A tunnel of hardened lava along Maui’s famous Road to Hana.

Take shelter from Hawai'i's tropical heat under the massive canopy of largest Banyan tree on the island.

Miles of man-made caves and tunnels are currently used for cultivating mushrooms.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

At Monet's beloved home you can still see the Japanese bridge, waterlilies, and weeping willows that were the subjects of some of his most iconic paintings.

The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.