This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

The last bastion of Roman presence north of the Alps looms over a German town.

Ancient serpentine sacrifice holder that has stood the test of time.

A marvel of Byzantine engineering under the streets of Istanbul.

Underground monastery and fortress.

A museum glorifying the life of Stalin, located in the city of his birth.

Rock-hewn monastery complex with hundreds of cave structures tucked away into the mountainside.

Nestled in a peaceful valley, this Armenian monastery may have been saved from Mongols thanks to the eyes of God.

The most visited pilgrimage site in Armenia once held a saint in a pit for 13 years.

A geological oddity topped with a 2,000-year-old pagan temple.

This Armenian monastery was carved out of cliffs and named after the spear used to stab Jesus.

The charmingly disheveled clock tower of Tbilisi's puppet theater.

Victorian "Fancy Craft" Hair Wreaths and Relics.

A modern day curiosity cabinet.

This brightly made over hotel hides decades of suicide, serial killers, and mysterious deaths.

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

The legendary building that needed ghostly approval before being built.

This quirky Arkansas wax museum does not shy away from the macabre and the grotesque.

When ecosystems collide in the arid Southwest.

A little-known hot spring haven right below the highway.

Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

The superstar of Cold War nuclear bunkers has been featured in countless films but is now barely operational.

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