The mass grave of a heroic Revolutionary War regiment sits below an empty lot near the Gowanus Canal.

This small museum in a former church crypt contains artifacts of the Elephant Man, Jack the Ripper and Florence Nightingale.

Caves full of Buddhist statues, incredible rock formations and a deserted lagoon.

The ruins of an ancient city built by Mayan traders is centered around a temple of a sacred feathered serpent deity.

A Canadian POW for German soldiers during WWII where prisoners hatched an elaborate escape plan.

Designed by Buckminster Fuller, this relic of the 67 Expo survived fire and ice.

This former lieutenant governor's home is brimming with curiosities.

A unique form of erosion created an uncanny landscape of boulders perched atop slender columns of clay.

Left untouched since a double murder-suicide in the 1960s, Los Feliz murder mansion remains a neighborhood mystery.

A beautiful, dense forest in the shadow of Mount Fuji, with a tragic reputation.

A treasure trove of astronomical, mathematical, and scientific instruments at Cambridge University.

Thanks to the building of a life-giving reservoir, part of the Great Wall of China is now a dive site.

One of the last active volcanoes on the Eastern seaboard.

This colossal war machine is now a living museum dedicated to underwater warfare.

A 19th-century Gothic, castle-like statehouse by the Mississippi River.

Life-size bronzes of the Grinch, Cat in the Hat, Yertle the Turtle, Sam-I-Am, and the Lorax—and the author himself.

Built to ward off Napoleon's army, this city-sized abandoned Russian fort is now perfect for urban exploration.

Now isolated, this church was once the center of a bustling village that succumbed to the Black Death.

The "last holdout of the Confederacy” actually sat at the edge of the Canadian border.

The 1936 Summer Olympics site is a crumbling remnant of sportsmanship and a history its host country would like to forget.

A memorial to the unknown and unheralded men and women of the Cold War military and intelligence services.

This iconic 1,000-year-old medieval castle is a favorite of the film industry, most notably as the location for Hogwarts in Harry Potter.

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

A medieval replica of King Arthur's legendary table, the Round Table hanging in Winchester Castle was decorated by Henry VIII.