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

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

Northern Ireland's Brobdingnagian stepping stones.

Mortarless walls that stretch for miles are a lovely solution for creating grazing land in the harsh terrain of the Aran Islands.

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

This ominous Albanian fortress houses tanks and downed planes as a reminder of their victories over Western imperialism.

Puffin enthusiasts flock to Europe's largest seabird cliff, which over one million birds call home.

This stunning concert hall has become a symbol of Iceland's national recovery.

This tumultuous Icelandic lava field looks so alien European researchers want to use it as a stand-in for Mars.

These ominous lava formations were said to be an entrance to the netherworld so of course they inspired a famous metal band.

Iceland's largest lagoon is home to stunning multi-colored icebergs.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Medicinal spa created with the discharge from a geothermal energy plant.

The oldest steel ship in Iceland has been beached for years and is now a rusting ruin.

Quite simply the largest tree in the world (by volume).

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

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

Rippling sand dunes frozen in the Arizona rock.

Most-visited and most-photographed slot canyon in the American Southwest.

This "dead marsh" sits among the largest sand dunes in the world, a forest frozen in time.

Bizarre living fossil only grows in a small chunk of the Namib Desert.

Ancient artists in the middle of nowhere.

The largest known meteorite on Earth was too big to move.

This rusting remnant of the local herring industry is being given a second life.