America's silhouette includes 100 square miles of wilderness jutting into Canada thanks to an old mapmaking error.

This mechanical wonder towers above a river in Michigan's capital city.

A cannon designed to fire an atomic warhead.

This hidden treasure is the world’s oldest active geocache.

Kentucky's anomalous peninsula projecting into the Mississippi River, site of legendary earthquakes and local feuds.

The world's longest known cave system.

The third tallest lighthouse in America once guided author Stephen Crane to safety.

A building so large that it has its own weather.

These ancient ritual mounds are our best window into the culture of the ancient Mississippians.

This historic graveyard was partially paved over to create a streetcar line.

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

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

This little museum in the town where zombies were born celebrates the living dead.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

A small storefront museum explores the history and myth of West Virginia's famous urban legend.

The first declared National Monument in the United States.

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

The phrase "the shot heard around the world" was coined after a skirmish at this bridge.

A plaque marks a former safe house on the secret route, now hidden next to a McDonald's.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

Twin Peaks' real life Double R Diner has been restored to its damn fine television look.

Train debris from the deadliest avalanche in United States history can still be found in the ravine where so many perished.

The site of the Wellington avalanche, one of the America's worst railroad disasters.

Eternal resting place of the grave robber and murderer who served as inspiration for many of cinema’s famous madmen.