The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A beautiful geyser under environmental threat.

The first declared National Monument in the United States.

Unlike other abandoned asylums this empty institution welcomes visitors, just don't go in the buildings.

One of the now-less-hidden floral gems of the "Emerald Necklace."

The walkable ruins of an 19th century hotel, destroyed in a horse cremation gone wrong.

One of the most scenic falls in Massachusetts has a history of death and grim legend.

The often-overlooked ruins of one of the first buildings designed by famous landscape architect Frederick Olmsted.

An eccentric inventor's castle home with its own indoor weather system.

Ralph Waldo Emerson spent two years living here decades before it became a Frederick Law Olmsted-designed park.

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

An enormous, inside-out glass globe built in 1935.

This upscale streetwear store is hidden behind a fake Snapple machine in the back of a deli.

A labor of love built by local hang-gliding enthusiasts, this ideal launch spot was outlawed by the authorities and has since been largely abandoned.

This former asylum for Black Americans is haunted by its history of violence and racism.

This Maryland farm is known for its amazing corn mazes and its 30-foot junkbots.

This abandoned Victorian-style house was built in 1884.

Remnants of a storybook amusement park hidden behind a strip mall.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

The "Sultan of Swat" once attended a school at the site of this baseball field.

The smallest covered bridge in Maryland.

This Asian-inspired tower in a lush urban park provides spectacular panoramic views of Baltimore.

FDR's Art Deco hospital tower was hopelessly inefficient.

Although built to generate electricity for Marylanders, this dam has become an all-you-can-eat buffet for American bald eagles.