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

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

A house carved into a rock in the 1940s.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

The tea room that pushed the boundaries of adorable straight into...we can't find the words.

The oldest surviving synagogue in New York City is now a soaring art space.

St Bernard de Clairvaux Episcopal Church, better known as one of the oldest European buildings in the Western Hemisphere.

When ecosystems collide in the arid Southwest.

Nikola Tesla's former home contains an homage hidden from plain sight.

This charmingly homemade amusement park has been growing for 40 years.

An essential stop before plundering, BYO Cutlass.

The highest bridge in America was built for an almost unnervingly small amount of money.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

A bizarre roadside attraction and the first instance of miniature golf in the world.

European castle ruins in an American state park are actually the product of death and grief.

The oldest operating apothecary in the US has treated everyone from Thomas Edison to Mark Twain.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

A colorful architectural gem in Seattle's uniquely modern Central Library.

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

Crammed into a Baltimore row house is an oddities shop that sells everything from skulls to dead insects.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

A meditative space out of a fantasy story.

An antiquated German apothecary on Chicago's North Side.

A clear blue swimming hole with hidden caves, still unexplored.