Huge abstract sculptures of the Puerto Rican Flag.

Small and slightly hidden, the American Writers Museum is preserving the legacy of America's finest authors.

This bronze sculpture on a former squash court marks the secret origins of the Atomic Age.

A military museum and library dedicated to the citizen soldier.

Home to a protest movement, a bombing, and a dramatic change in labor history.

This modest post office sits on the site of H.H. Holmes' famous murder castle.

These pretty kitties killed and ate as many as 135 railway workers.

A gothic church spire sits atop this skyscraper, the tallest church in the world.

A lush green oasis in the middle of Chicago.

The world’s largest underwater sculpture is found just off the coast of Nassau.

This staircase in a lush tropical grotto was built by enslaved laborers and renamed to honor Queen Victoria's role in ending slavery in the British Empire.

A museum honoring Oklahoma military service, where you can look into Hitler's mirror and see a Mickey Mouse gas mask.

An old spiral fire escape dangles above a public courtyard in Midtown Oklahoma City.

Nature's biggest mammal swims in landlocked Oklahoma.

The fifth tallest statue in the United States is a shirtless monument to the oil worker.

This abandoned, windowless concrete block is one of the strangest buildings in Tulsa.

A Montreal deli that was so beloved that it was allowed to circumvent their laws of language.

Every year, the colorful murals of Montreal get a complete makeover.

Two adjoining collections of 19th-20th century physics apparatuses and instruments.

This elaborate towering structure was once famed for its revolutionary height.

World's first "penitentiary," meant to be humane, drove men insane.

Contrary to popular belief, this secluded statue doesn't represent Pennsylvania's founder.

A layered tribute to the work of mosaicist Isaiah Zagar.

The first American department store, and home to the largest operating musical instrument in the world.