The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

This tangled English forest looks like something right out of a fairytale.

Legend says these rocks used to be hunting dogs, a story that may have inspired Sherlock Holmes' most famous case.

The legend says that this English rock formation was once a hunter who was turned to stone by annoyed witches.

These medieval tunnels provided water to the city above through centuries of civil war and plague.

At just 25 inches at its narrowest point, it's one of the tightest streets in the world.

The home of one of America's most wealthy industrialists is now a historic site that remembers a more decadent time in the country's history.

Oldest existing church in New York and the inspiration for Washington Irving's "The Legend of Sleepy Hollow."

The Hudson River School comes alive at this palatial estate.

The life of one of FDR's possible mistresses is preserved in her palatial Hudson Valley mansion.

This impressive Boston holy house is the American mecca for Christian scientists.

This monument on Breed's Hill proves that one of the most famous battles of the Revolutionary War is misnamed.

One of the oldest used bookstores in the U.S. has been selling antiquarian treasures since 1825.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

Two thousand artifacts from around the world collected by one woman who loved to travel.

This lighthouse and shipwreck museum keep a torch burning for the memory of the SS Edmund Fitzgerald.

Mysterious 500-year-old tapestries depict a unicorn hunt.

Small monoliths of several varieties of stone sit alongside a wooded path in the Bronx.

This plot of old-growth forest is the largest surviving remnant of New York City's original woodland.

A graffiti Mecca welcoming artists from around the world.

Read between the lines of the subway map to find the hidden abandoned Civil War fort.

This abandoned seaside fortress is now simply an imposing ruin being taken back by nature.