Hundreds of glow-in-the-dark objects light up a museum in a historic zinc mine.

A museum dedicated to exhibiting remarkable outsider art.

An outlet for connecting to memories of lost loved ones and saying goodbyes you never got to say.

The Ryerss mansion in Burholme Park now houses a community library and a museum filled with a trove of oddities from around the world.

One of the world's oldest continually operating bookstores.

One of the U.S. Forest Service's only mansions is outfitted with a dinner table for floating food.

This Pennsylvania cave holds evidence of the oldest known inhabitants of North America.

Frank Lloyd Wright built this suburban synagogue late in life, but it stands among his most iconic masterpieces.

With 3,000 bikes on display, the world's largest bicycle museum includes some famous rarities.

The house that Frank Lloyd Wright "(shook) out of his sleeve at will" at the age of 86.

Dr Barnes' $25 billion private collection of art and arboretum.

Mutant vegetables, transgenic mosquitos, and atomic rodents span the walls of this one-of-a-kind museum.

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

World's first "penitentiary," meant to be humane, drove men insane.

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

A lawn full of retired spacecraft on display at one of NASA's first research labs.

Sip colonial-era cocktails at this monthly recreation of a 1740 watering hole.

A drab two-story office space in Delaware is a hidden tax haven for Hillary Clinton, Donald Trump, and over half the Fortune 500 companies.

This local gem houses the largest collection of pre-Raphaelite paintings outside of the U.K.

A blend of art, antiquities, and Americana fill this museum, surrounded by whimsical, enchanting gardens.

This splendid Versailles-inspired mansion has the largest French-style formal gardens in North America.

Western New York's largest independent bookstore doubles as a historical repository of all things Niagara Falls.

The childhood home of the Sultan of Swat is just a line drive away from Oriole Park at Camden Yards.

George Washington's dentures and Queen Victoria's dental instruments are in the nation’s official museum of the dental profession.