This maze-like slot canyon is a unique gem within an already fascinating geological area.

One of the last active volcanoes on the Eastern seaboard.

A scenic fort on the harbor protected Philadelphia from an attack that never came.

One of the only memorials dedicated to journalists who died in combat.

An eerie, decaying ghost town destined to fade into the forest.

Perched above the bustling town of Kerak is a sprawling, ruinous castle that has witnessed nearly a millennia of Levantine history.

This former Texas landfill is flush with 300 million-year-old fossils, all fit for the taking.

Rich red almandine gemstones are waiting inside the volcanic rock strewn across this eastern Nevada hillside.

A watering hole where the options for seating include a bar, patio, or subterranean cave.

This cave was hidden for thousands of years, storing the worldly goods of ancient Native Americans.

Wee (and not so wee) footprints that insects and reptiles of the Paleozoic Era left behind.

A natural history wunderkammer in the middle of the desert.

America's only nuclear missile silo open to the public.

Singing sand that stands as the final remains of an ancient lake.

One of the most remote spots in America and the first protected wilderness area in Nevada, named after an old legend.

A volcanic landmark located on an Ice age lake bed.

A volcanic fissure over two miles long and up to 70 feet deep.

This beautiful ancient site is dotted with perforated sandstone pillars considered sacred by some Native American groups.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

"We Seceded Where Others Failed."

The site of the little-known Pennsylvania battle that sparked the Seven Years' War.

Thousands of unique minerals, including some of the most impressive fluorite crystals in the world.

The famous aviator's final resting place is a study in natural beauty.

A tunnel of hardened lava along Maui’s famous Road to Hana.