Street artists transformed an abandoned air vent into the beloved Star Wars robot.

Why walk on this historical site when you can zoom down instead?

The Pope’s secret escape route.

A miniature rainforest is growing inside of a Midtown Manhattan office building.

Installed at a chaotic intersection, this gave London traffic cops a place to hang their heavy woolen coats.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

A room hidden behind a swinging shelf in the children's section.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

One man's dream has turned into this naturally growing chapel made of almost nothing but trees.

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

A creepy sculpture of a decapitated head invites viewers to see St. Louis through its empty eyes.

The 16th-century church was kept in its ruined state as a reminder of the casualties of World War I.

Once in disrepair, this popular Texas stop along iconic Route 66 has been restored to its past glory.

Though technically an illegal structure, this eclectic DIY apartment complex is beloved by its residents.

The small family-run business has kept alive the fading art of creating beautiful handmade book covers.

The vertical-axis windmills of ancient Persia have been grinding flour for 1,000 years and counting.

These ancient sunken lanes were naturally tunneled into the soft ground by countless footsteps.

Deep in the countryside lie the remains of one of the grandest Roman dwellings in Britain.

The oddly shaped, steam-spewing building is now an art studio and gallery.

Elaborate patterns adorn the city's disappearing traditional architecture.

An eight-sided home built during a brief octagon craze in the 1850s.

The skeletal white beams stand as a monument to religious dissent.

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

This charming railway is one of the oldest and steepest funiculars in England.