The largest self-built castle in the U.S., six decades in the making.

The only retired U.S. nuclear missile silo that is open to the public.

Creek water that starts here has a 50/50 chance of ending up in the Atlantic or the Pacific.

This prison-turned-museum is a remnant of the Old West's grizzly, violent past.

One of the smallest towns in the United States.

A rapidly disappearing glacier filled with extinct grasshoppers, perfectly preserved in the ice.

This off-the-beaten-path abandoned town is a relic of Montana's silver mining boom.

This angular Dwarven tunnel cuts through a mountainside in Glacier National Park.

This amazingly preserved Gold Rush town is a historian's dream.

Civil War soldiers, captains of industry, and paupers all interred on historic grounds.

An abandoned railroad tunnel forgotten by time awaits inquisitive hikers.

The perfectly named cave drop is the deepest in the continental United States, almost matching the height of Seattle’s Space Needle.

The largest cemetery in the American Southeast is a hidden gem near the heart of Atlanta.

One of the largest-ever mental hospitals now sits abandoned, surrounded by 25,000 unmarked graves.

Tour the sci-fi-esque reality of governmental disease management.

Over 100 million years ago, beach-bound dinosaurs left permanent marks on San Antonio's landscape.

Ruins of a once-opulent grand Victorian resort.

This small town Texas cemetery is said to be the burial site of a UFO pilot who crashed in the 1800s.

This sacred cavern, 400 feet deep, is home to millions of bats and an ancient burial ground.

An oddities shop packed with twisted treasures inspired by Oscar Wilde and Edgar Allan Poe.

An abandoned quicksilver mining town surrounded by the Big Bend parks.

A medieval castle in the middle of rural Texas.

This crumbling UFO is one of only a few remaining "moveable ski chalets" of its kind.

A Victorian mansion, painstakingly reproduced to appear just as the the Munster's family home did on TV.