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

The Aldie Gristmill was once the largest factory of its kind in Loudoun County.

The bridge's highly-contested plaque (once again) honors Confederate President Jefferson Davis.

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

The only surviving 19th-century water-powered mill found in the Washington, D.C. area.

This pun was simply waiting to come to life, and one defense contractor made it so.

Home to one of the tallest church spires in Europe, this historic church once played host to King Henry VIII and Anne Boleyn.

Visit the WWII bunker where the British won the battle for the skies.

England's oldest surviving hedge maze has been confusing visitors for over 300 years.

Legend has it that seven Anglo-Saxon kings were coronated on this stone, located in the appropriately-named town of Kingston.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

A little slice of Japan and its aesthetics in London's Holland Park.

Catacombs turned marketplace.

This pub was 238 years old when it decided to revamp its image: It started serving Thai food.

The grounds of this Jacobean estate contain one of the oldest mulberry trees in England.

The rose garden in Regent's Park where Pongo and Perdita met for the first time in Disney's "101 Dalmatians."

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

Putting the "mod" in "modular" since 2000.

The bones of two medieval royal lions were discovered at the historic fortress.

This marine reptile was discovered by one of the 19th century's greatest fossil hunters.

Never actually a tree at all, this spot was the site of London's public hangings for nearly 600 years.

The pockmarks across the building's facade are remnants of the Blitz.

Revel in the Victorian splendor of the world's oldest eating establishment inside a museum.

The remains of the great moral philosopher reside in a university in London.