A thin pane of glass keeps visitors from sliding off this futuristic skywalk.

Walk behind a 50-meter-high waterfall.

This "preacher's pulpit" once used for pagan ritual, is home to a new, and dangerous ritual.

This giant boulder is pinched over a 1000-meter abyss by two mountains.

A serpentine highway twists and turns over the treacherous Norwegian Sea.

Walk 2,300 feet above the ground on the "Troll's Tongue."

An abstract monument to a symphonic composer.

An alien church provides much needed silence in the midst of a Finland shopping center.

A subterranean house of worship carved right out of the bedrock.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

The tallest outdoor elevator in Europe rockets passengers on a dizzyingly precarious ride to the top of a mountain.

Caves famous for the dragon-slaying saint who lived there.

The alleged house of the Virgin Mary is tucked away in a park and nature preserve on Mt. Koressos in Turkey and is holy to both Catholics and Muslims alike.

Roman ruins top white travertine terraces formed by ancient hot springs.

One of the best-preserved modern fortresses was part of a pivotal moment in the Italian Risorgimento.

Stuck in the arcade of Casa Isolani are three arrows of mysterious origins.

One of the tallest bell towers in Italy plays a particular melody at just two times each day.

This amazing medieval fortress stands atop a promontory along the famous Cinque Terre.

Italy's only urban waterfall has enchanted artists and travelers for centuries.

A rare example of an octagonal Catholic church.

The home of a neoclassical master is now a shrine to his chosen art style.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

Legend has it this fountain built to symbolize the Pope’s power hides a strange secret concerning Neptune's manliness.