The site where Poe "in great distress, and ... in need of immediate assistance" likely died.

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

Quite simply the largest tree in the world (by volume).

See massive fossils that are over 200 million years old in northeastern Arizona.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

The trials and tribulations of marking Poe's grave.

San Francisco's newly reopened hands-on science museum.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

The world's longest known cave system.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

A beautiful geyser under environmental threat.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

The first declared National Monument in the United States.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

An historic and oft-filmed spot for musclebound iron pumpers on the Pacific coast.

Her final resting place was intended to be modest and private, but the power of her popularity continues to draw visitors.