Found art has transformed this Pittsburgh neighborhood into a psychedelic dream.

A throwback train ride transports passengers through one of the lesser-known national parks in the country.

Faces carved into the cliffs create an otherworldly walking trail.

A mysterious echo seems to defy the laws of acoustics.

"A hideous albatross in the Hudson River Valley."

A grotesque Fiji merman dwells within this traditional Dutch-style building.

Designed to commemorate the founding of the first settlement in Delaware.

The historic home still shows the scars from a little run-in with the British in 1813.

WWII-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers. .

The library of every book lover's dreams.

A layered tribute to the work of mosaicist Isaiah Zagar.

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

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

A mailbox that saved a nature reserve.

The highest point in Tennessee, Clingmans Dome bears witness to the ravages of one type of insect.

The location where the American Revolution ended.

This museum explores the grim reality of life in the earliest British colonies in America.

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

America's post-nuclear-attack chambers of Congress.

This tree is a living witness to the beginning of the Civil Rights Movement.

Scenic mount trashmore, Virginia Beach's most curious waterfront still has a couple of secrets.

Down the road from where the Wright brothers lifted off is another flight tribute practically hidden from sight in the woods.

This shifting North Carolina sand dune is an odd little desert surrounded by oceanic forest life.