Naturally formed rock city in Poland.

These tiny book repositories are inspiring new readers across Northern Ireland.

An atmospheric, medieval-themed book store hides in a 13th-century underground space.

A verdant 17th-century-style garden hidden along Edinburgh’s Royal Mile.

The final resting place of a prominent Chippewa chief and several Native American children.

A grave surprise in the downtown area of New England's second-largest city.

A small, forgotten prison cemetery marked only by a wrought-iron fence and eerie depressions left in the ground.

Two Civil War-era cemeteries stuck between runways at the world's busiest airport.

The sole surviving relic of the San Francisco neighborhood cobbled together from old horsecars and streetcars.

One of Frank Lloyd Wright's greatest—and favorite—architectural masterpieces was almost lost.

This romantic, decaying 13th-century ruin on the edge of Sherwood Forest is reputedly one of England's most haunted places.

Legend said this huge, gnarled tree sheltered the saint during a storm.

This enigmatic stone pool is all that remains of an ancient palace.

This theme park presents 5,000 years of Shanghai history and includes a "sunken" exhibition hall.

This beautiful and unmissable little museum is full of fascinating artifacts from Mesoamerica's great civilizations.

Before Nixon, "watergate" meant canals.

The hidden offices underneath Memorial Bridge have been locked up since 1976.

The world's second largest single-dish radio telescope, once used to contact E.T.

The largest geyser field in the southern hemisphere is a spectacular sight.

A desert that evokes the surreal.

You can swim in these highly salty, mesmerizingly blue lakes in the Atacama Desert.

Replicas of fossils unearthed during renovation work reveal how this area would have looked millions of years ago.

A derelict bit of transportation infrastructure hidden in the woods.

On a wall in Cleveland, Ohio find the story of a highly connected fictional community of organisms that created remarkable, lasting structures.