This WWII-era military installation once held an entire city within its walls - now, its walls are falling down.

An abandoned aircraft sits submerged in a lake in the Alaska wilderness.

This partially buried wreck is one of the most complete of its kind but is only revealed when the sea allows.

Deadly airliner crash preserved for those willing to climb and pay respects.

This long, dark tunnel is open to hikers, but those without lights are known to get confused even on the straight path.

This historic steamboat is scuttled just a few hundred feet from where it was built over a hundred years ago.

A heavenly experience, right here on Terra Firma.

A stunning landscape of bunkers that once stored chemical weapons.

The world's smallest park was dedicated in 1948 as the only colony for leprechauns west of Ireland.

Gigantic private toy museum featuring among finest collections of antique mechanical banks in existence.

Beyond being incredibly fun, not much can be said about the Hole with certitude.

This extinct shield volcano is the lightning rod of the Cascades.

1920's mining camp and environmental education center is serving to protect the surrounding forest, one of the last of its kind in the Pacific Northwest.

Hollowed out cedar log tubs set in an ancient towering forest.

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

A volcanic landmark located on an Ice age lake bed.

Massive crater in central Oregon.