This London plaque marks the spot where David Bowie's famous alien made his debut.

This London marker celebrates the spot where the world-famous English band was founded.

This five-star hotel was originally a swanky parking garage.

A plaque marks the underground site of one of London's "lost rivers."

It is still illegal to "quarrel" at this unlikely urban oasis built on top of an electrical substation.

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

A tiny, hidden alleyway dedicated to the father of meteorology.

Hidden on the urban banks of a Manchester river are a series of abandoned waterside industrial sites.

The small bright red pillar survived the 1996 Manchester bombing virtually unscathed.

The remnants of a depressing public toilet are now a hub of ever evolving street art.

A tiny, heartwarming piece of art hiding in plain sight.

A plaque pays tribute to the artist's longtime London home.

Black cat statues guard this temple-like Egyptian revival factory.

The next-door homes of two very different musicians, George Frideric Handel and Jimi Hendrix.

A closed London rail station created to cart away the dead still bears the marks of attempts to make it less morbid.

A hands-off space for graffiti artists to hone and display their skills.

A mysterious carving from 17th-century London seemingly depicts a young boy sitting on a bread basket.

You'd never know the houses at 23-24 Leinster Gardens were fakes—until you see the train tracks on the other side.

The famous polar explorer stands outside the Royal Geographical Society's headquarters.

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

This nondescript building hides an entrance to an underground nuclear tunnel system.

Manchester's abandoned train depot lingers in a post-industrial purgatory.

A hunk of prehistoric lava rests amid the Gothic architecture of a campus quad.

Despite having a dome made of papier-mâché this tiny observatory has survived for over a century.