With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

At 207 feet, one of the world's longest continuous escalators.

The site of the climactic scene from the classic horror film is now a historic landmark.

Once a favorite playground for the world's most illustrious guests, Hotel Nacional's secret weapons and bunkers reveal a more menacing side to its golden history.

The first official clock in North America, it kept time for the Spanish government of Santo Domingo.

Built in 1512, the oldest cathedral in the Americas.

The royal seat of Henri Christophe, a formerly enslaved man who became Haiti's only king.

This iconic fortress was once the crown jewel of Haiti's national defense.

This elegant Colombian fortress was one of the torture headquarters for the Spanish Inquisition.

The modern birthplace of Irish freedom.

360° views of the city plus five floors of optical illusions and hands-on science.

Huge winged monument in the United Kingdom.

This hidden natural fountain issues forth a steady supply of supposedly healing water that tastes like rotten eggs.

One of the oldest amusement rides in existence was a huge disappointment to its creator.

The oldest inn in England served brew to the crusaders.

Scattered throughout London are ancient remnants of the city's former bounding wall.

Eighty million natural history specimens call this gargantuan museum home.

Pop culture has helped to keep this iconic British building from being destroyed.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

Bronze sculpture celebrating the relationship between Churchill and Roosevelt.

One part local history, 99 parts gruesome haunted house.

This luxury shopping lane has been protected by its own tiny police force for over a century.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.