A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

Elevated freight railway turned wildly successful urban park.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

This ancient walled garden turns fog into food.

A hidden architectural treasure in New York's Brooklyn.

I fought the law and the precinct caved in.

Detailed facade of a brownstone in Boerum Hill.

A band of aerialists and circus performers putting on incredible shows in East Williamsburg.

A shop full of natural curiosities, carnivorous plants, and costumed taxidermied mice.

The remains of a centuries-old water system that inspired local legends of secret tunnels.

This often-overlooked ocean walkway was once considered an impossible fantasy.

This amazing collection includes rare stamps from around the world, including fluorescent ones.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

A Spiritualist house of worship where believers communicate with the dead in the spirit world.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

This beloved marketplace mascot poops money and grants good luck.

A tiny, unmarked beer and whiskey bar above an Ethiopian restaurant in West Philly fails to conceal live bluegrass.

The first American axe throwing club.

Stay in a room with a view... of the bottom of the ocean.

An eclectic treasure trove of maritime marvels.

A haunted hill that supposedly defied gravity.

Possibly the most beautiful carillon in the world, set atop Iron Mountain in Florida.