The home of one of America's most beloved fictional characters has become a real world landmark.

Spies, love letters, and ghost stories have all left their mark on this home-cum-museum.

The rustic think-space of famed naturalist John Burroughs stands exactly as he left it.

This castle-like building in Manhattan helped destigmatize cancer in the 19th century.

This small road tunnel is the only place where you can cross beneath the Erie Canal.

What happens here stays here – unless it affects the whole world.

Museum dedicated to the struggles of the disabled.

Self-sufficient greenhouse floating on the Hudson River.

Astonishing collection of helmets, scientific instruments, and medical models.

This collection started by a Cornell professor once held more than 600 human brain specimens, including the one that belonged to its founder.

The first evidence of some of the Earth's earliest life was found in this fossilized undersea grotto.

Piano-making empire filled with 200-year-old steam machines still churning out 1,000 instruments a year.

A Bed-Stuy gymnasium that hosts expansive raves, performances, dance parties, and more.

This otherwise innocuous bodega was once the headquarters of the most feared assassin's guild in American history.

Harlem park dedicated to compulsive hoarders killed by their own junk.

Phil Mortillaro uses keys to bring art back to the Village.

The New York hotel where tragic visionary Nikola Tesla spent his final hours, destitute and alone but for the pigeons.

Protecting the future of some of the rarest and most misunderstood mammals of North America.

An unrealized dream to wirelessly electrify the entire Earth.

The world's oldest hologram gallery and the labyrinthine laser laboratory of a holography pioneer.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

Tucked in the back of this amazing antique store is an important piece of medical history.

Hidden for 165 years inside a building designed by Thomas Jefferson are the remains of what may be America's first educational chemistry lab.

Huge otherworldly domed rocks on the shore of a deadly lake.