A 19th-century horse lover's bequest led to the construction of this unique fountain in Chicago.

The only Bahá'í house of worship in North America and one of only a handful worldwide.

This alley in downtown Chicago held the bodies of over 600 people after the fateful Iroquois Theatre fire.

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

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

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

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

This private residence was the template for one of the most beloved television homes of all time.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

A spiritual sanctuary in a natural cave.

The charmingly disheveled clock tower of Tbilisi's puppet theater.

Teeming with illegal goods and services, this towering maze of vice is also a popular tourist accommodation.

The awe-inspiring ship from the golden era of cruising has an incomparable history and a reputation as one of the world’s most haunted places.

These chunky stone towers out in Lake Michigan are the key to Chicago’s drinking water.

No one knows how many bodies are in this vault in a Chicago public park.

The space-age building is home to one of the few remaining rotating restaurants in America, and the only one that inspired a 1980s sitcom.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

An out-of-place slice of France, smack in the middle of Shanghai.

Climb to the top of the world's largest seated bronze Buddha.

A monument celebrating the idea of reaching inaccessible places.

A giant Troll lurks under one of Seattle's oldest bridges.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

Geometry and mystery come together in an epic show of octagonal masonry.