These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

Two plaques commemorate the site of Shakespeare's first theatre.

This Welsh village gave itself a ridiculous name in a publicity stunt a century ahead of its time.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

Horse cemetery on the grounds of Blarney Castle.

A sweet symbol marks the place where torturous executions were once carried out.

A labyrinthine network of chambers with a storied past hides below Edinburgh's South Bridge.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

A spectacular remnant of an Adler and Sullivan masterpiece that was destroyed in 1972.

Once at the center of U.S. finance, the historic Trading Room was meticulously recreated piece by piece and rebuilt in the Art Institute.

A 400-foot-tall tall map of Chicago makes this once-ignored building stand out.

This awkward aquarium sculpture is one of the strangest statues in Chicago.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

This $3 million model train takes you through Chicago, Seattle, and the thousands of miles in between.

What's left of the ruins of the 1893 Columbian Exhibition, or World's Fair, also known as the White City.

Each of these gorgeous, intricately decorated rooms is painstakingly crafted to the scale of 1 inch: 1 foot.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.