Take a self-guided tour through one of Colorado's most elevated mining districts.

This once-popular otherworldly landscape was formed by one of the largest volcanic eruptions in history.

Unlike most arches, this geological oddity formed in a volcanic dike.

The haunted reputation of these abandoned Colorado train tunnels is probably not helped by the terrifying spiked fence.

This grand stone tower was dedicated to a famed American humorist almost by coincidence.

Meet Rita the Rock Planter, one of Danish sculptor Thomas Dambo's enormous wooden trolls.

An abandoned sawmill from more than 134 years ago stands testament to the ambition of one man.

Located in the world's highest-altitude Dark Sky Community, this observatory welcomes amateur and professional astronomers alike.

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

A registered historic landmark shrouded in unsettling local legends.

A former hospital is now home to a pizza parlor and maybe a few ghosts.

This now-deactivated naval base defended the Florida coast for centuries.