Enormous lake at the bottom of a unique cave system.

At 135 years old and counting, this historic print shop is heaven for poster nerds and music buffs.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

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

Edgar Allan Poe's old dorm is now a shrine to the author's legacy.

Eighteen miniature death-scene dioramas.

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

A 19th century library favored by Edgar Allan Poe and H.P. Lovecraft, known by locals as "the Ath."

Two thirds of this Montreal neon icon has survived to flash another day.

Trinkets and toys lovingly handmade by maximum security prisoners.

The world's largest woodcarving collection includes dozens of Bible scenes and a wooden bestiary, all carved by one man.

Bar full of oddities, specimens, artifacts and homages to the great dime museums of the past.

A house built from trash known as the poor man's Hearst Castle.

One of only two commuter aerial tramways in the United States.

An astounding collection of medical specimens, including bits of President Lincoln.

Hear the quietest sound from across the dome.

One part local history, 99 parts gruesome haunted house.

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

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

An artist's cute bronze subway sculptures belie his violent artistic past.

This museum on a college campus pays tribute to the Arctic and to two explorer alumni.

A limestone wonderland of water and subterranean secrets.

This bridge made famous in a novel and on-screen wasn't actually built over the river Kwai.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.