The oldest alley in San Francisco is paved with a reminder of the city's original shoreline.

These six walrus head statues harken back to a time when this area wasn't far from the oceanfront.

This edible park is open to any and all foragers.

This sinkhole in the Arizona desert is filled with carbonated, arsenic-rich water

This small, unassuming street is now a canvas for color and creativity.

This small interfaith chapel lies not far from the rim of the Grand Canyon.

The remnants of a creative early method of wildfire prevention.

This former coal gasification plant found a curious second life as a popular public park.

Throughout this shopping mall are medieval ruins that were discovered during the mall's construction.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

The oldest garden in Prague, once part of an medieval orchard.

Countless grotesque faces stare out from this eerie Prague art wall.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

A series of playful yellow penguins share a serious message about the environment.

This doorless 20th-century elevator doesn't stop or slow down.

Macabre astrological automaton clock dating to the late 1400s.

Nine bronze hands protruding from a wall honor the student uprising that led to the fall of Czechoslovakia's Communist government.

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

A Jenga-style cylindrical tower of books that appears to go on forever.

What looks like a suicide in progress is actually a statue of Sigmund Freud.

Walk through Czech history in Prague's largest graveyard.

Straight out of a nightmare, barcode-faced babies climb up and down Prague's television tower.

Looming communist pillar with a Czech twist.