A simple but powerful tribute to the 20 victims of the 1692 witch trials.

A luxury hotel constructed out of a former jail.

A three-piece musical sculpture installed between the subway tracks at Kendall Station near MIT.

One of the last remaining movie theatres in the country that features a rear-projection system.

Kwanu'sila the Thunderbird has been silently watching over Chicago for more than 100 years (kind of).

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

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

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

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

Partially submerged Buddha heads freckle Chicago’s neighborhoods.

This abstract sculpture is rumored to cast a hammer-and-sickle shadow once a year.

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

This surprising gem is a world-class archeological museum hidden at the University of Chicago.

A haunting statue called "Eternal Silence" has quite the reputation among visitors with active imaginations.

A strange and haunting monument of unknown origin in the historic Graceland Cemetery.

An enormous park-like oasis, full of famous Chicagoans’ graves.

A lush indoor jungle fills this bustling Madrid transportation hub.

This unassuming stone commemorates a condiment factory gone up in smoke.

Rising 30 feet in the air atop Quarry Hill, the Old Powder House is the oldest stone building in the state of Massachusetts.

This tiny, painted door at the base of a tree stump has been a fixture of the Harvard University campus for decades.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

The thousands of shades on display — some toxic, others impossibly rare — are a library of more than just color.

This huge pile of volcanic boulders hides a stunning network of secret grottoes.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.