This unreal Portuguese palace looks as though it's made from a pile of different castles.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

Rumored to be the famed pirate's lookout tower, this historic stone structure is now just watching for tourists.

The world's second largest single-dish radio telescope, once used to contact E.T.

The bat-covered home of one of the world's most popular brands of rum is located on a tropical Art Deco campus.

This chapel on a cliff is renowned for its healing powers and was founded on the site of a supposed divine intervention.

A forgotten relic from New York's bygone trolley system hides in plain sight under a bridge.

The one-time office of the architectural firm that ushered in the Gilded Age is now a Club Monaco.

Hordes of precariously balanced stone figures crowd the shores of the Hudson River.

This Upper East Side apartment co-op was designed as a tuberculosis sanitarium.

A 19th-century politician who died after walking home in a blizzard is honored with this Manhattan statue.

The only remaining building in New York to see the inauguration of a president is being slowly overtaken by a grocery store.

Nope, not Washington Irving's house.

Storage warehouse of the rich and famous.

This monument to a veteran of the Mexican-American War is one of only two in Manhattan that serve as an actual mausoleum.

These ornate manhole covers were used for a now-forgotten purpose.

This simple Manhattan salt house is artfully shaped... well, like a giant granule of salt.

This translucent sculpture represents a quintessential component of New York City's skyline.

There's a piece of New York City transportation history hidden in plain sight at a Manhattan subway stop.

The legendary court where emerging basketball players gain their street cred.

The former sign of this immortal music venue is just that--undying.

This anonymous businessman sculpted in bronze became an enduring memorial after 9/11, and had been mistaken by rescue workers for a survivor in the rubble.

The competition: breathe deeply as long as you can.

This vacant church in the Financial District was once the heart of New York's first Syrian immigrant community.