The story behind the mysterious symbol painted in front of the historic university's famous Rotunda.

This 29-ton granite ball spins around at the slightest touch thanks to a scientific phenomenon.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

The world's longest known cave system.

This candy shop has been serving up sweets to the Louisville area since the 1850s.

The resting place of a Civil War celebrity's amputated limb.

The Kirkland Monument remembers a selfless Civil War hero who braved the battlefield to give water to his dying enemies.

This war hero's old shop remembers the fine line between medicine and quackery during the Revolutionary War.

North America's largest accredited model railroad museum.

San Diego's most historic and haunted home.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

The last living thing to come out of the rubble after 9/11 is now a symbol of hope and resilience.

Blighted Irish field and the ruins of a 19th-century cottage on the edge of urban Manhattan.

A preserved college lock-up that recalls a clubhouse approach to discipline.

Sitting in the basement of a castle, the largest wine barrel in the world is bigger than most apartments.

This historic funicular system combines the old with the new while offering delightful views over the surrounding valley.

A memorial for a young woman and her ghost, which are claimed to have caused countless deathly shipwrecks.

Every hour the doors open to reenact the legend of the heroic mayor who saved his town by drinking a gallon of wine.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

Five candy-colored villages on the Italian Riviera.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

Home to items never before seen by the public.

The vast, legendary catacombs hold secrets much stranger than stacked bones.