These beautiful ruins deep in the Pennsylvania woods are thought to have been a ski lodge or a speakeasy, but no one really knows.

In an effort to escape the horrors of slavery, one man mailed himself to freedom.

A diminutive plaque recalls the treetop sniper who almost killed Abe Lincoln.

Though it may look like it’s missing its outer shell, this skeletal cast-iron tower was built to withstand wind and waves.

This home is decked out like a psychedelic explosion of colors and bowling balls.

A luxuriant botanical garden below sea level.

The only known working replica of the world's first self-propelled vehicle.

A stone memorial erected for New Hampshire's only convicted witch.

This small stone chapel is a hidden gem just outside the University of New Hampshire campus.

A quiet spot commemorating two naturalists who had to choose between love and the university at which they both taught.

A short nature trail winds through the greatest works of poet Robert Frost.

Annual celebration commemorating the 1965 sighting of strange lights in the town.

This dig site outside D.C. is known for its exceptionally high density of baby dinosaur fossils and dinosaur eggs.

This home is steeped in history from, George Washington to George Corwin, High Sheriff during the Salem Witch Trials.

One of the few places where you can visit a cenote and Maya ruins at the same time.

It would take you approximately an hour and a half to walk to the end of Mexico's largest pier.

This 5,000-year-old tomb once had its own hinged door.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

The world's first successful water-powered cotton mill paved the way for the factories of the British Industrial Revolution.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

One of the shortest streets in York has an especially odd name.

FDR's Art Deco hospital tower was hopelessly inefficient.

Color-coded signs direct drivers on a network of routes designed to avoid Pittsburgh traffic.