This hidden green space is the city's second largest conservatory.

A historic house left in "dramatic still life."

Catacombs turned marketplace.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

A kaleidoscopic warehouse-maze of handmade neon signs.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

A gazebo that inspired the fifth episode of the "Twilight Zone" still stands in the creator's hometown

This local landmark is home to art galleries and the area's only community darkroom.

The wooden octagon in which Huckleberry Finn and A Connecticut Yankee were born can still be visited in upstate New York.

This Art Deco fortress in upstate New York gives Manhattan's vaunted examples of the style a run for their money.

The absurd creation is a compulsory destination for selfies in Buffalo.

The seat of Buffalo government is a gorgeous Art Deco palace.

The site of William McKinley's tragic assassination is only marked by an underwhelming boulder.

This unique crypt designed by Frank Lloyd Wright for his longtime friend was not completed in either man's lifetime.

One of Frank Lloyd Wright's greatest—and favorite—architectural masterpieces was almost lost.

Montreal's giant farmer's market is a foodie's best friend, especially in the winter months.

One of Canada's oldest museums, the beautiful Redpath has been serving up Natural History and Ethnography since 1882.

Designed by Buckminster Fuller, this relic of the 67 Expo survived fire and ice.

This beautiful grotto is one of those places where you can't believe you're just outside Austin.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

An isolated island home to one of the oldest English-speaking communities in the region and Maryland's state dessert.

A historic cemetery filled with quirky faux wood art and unique tombstones.

An unusual sculpture, an interesting history, in a strange place, for a good cause.

One of the oldest anatomical theaters in the U.S. still in use was once the site of an infamous cadaver riot.