A decommissioned military complex that's now a modern industrial park.

A Manhattan office building is home to the world's largest chess board.

A discreet little stairway on St. Nicholas Avenue leads to a quaint and unexpected cobblestone street of 19th century wooden rowhouses.

This hidden oasis features a stunning view of the Hudson River and the Palisades from a castle-like museum.

The oldest Dutch colonial stone house in New York City is a hidden gem on the border of Brooklyn and Queens.

The end of the 4 Line is also the end of the line for 300,000 souls in one of NYC's most illustrious cemeteries.

Holding multiple historical boats and an entire 19th century village, this New England attraction is the largest maritime museum in the world.

This outpost of America's most popular fast-food restaurant is housed inside a palatial mansion.

Formerly the world's largest, this Willy Wonka-esque contraption runs 24/7.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

An abandoned asylum once on the cutting edge of lobotomies may be reborn as a Christian college.

The Hudson River School comes alive at this palatial estate.

The abandoned ruins of America's first private zoo are open for exploration in the Catskills.

This monastery built into a cliff hides a perfectly preserved hermit in a glass coffin.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

This ultra-modern burial building would have stacked the dead like a giant filing cabinet.

Those who own or stay at this 500-year-old, allegedly cursed house often meet terrible fates.

Two stone columns flank the grand Venice square, but there were supposed to be three.

Da Vinci's equestrian statue, 500 years in the making.

A slightly creepy gallery of plaster cast models in the same museum as Michelangelo's David.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

Erotic art covers the walls of the largest ancient pleasure palace.

Ancient snack bar of the Roman Empire re-opened.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.