The massive, incredibly rare instrument is over 11 feet tall with a range so deep it goes lower than humans can hear.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

The beautiful baroque library of the Hapsburg empire.

The stately remains of Llywelyn the Great's mighty fortress.

On the side of a remote mountain, a stone face bearing an inscription of mysterious origin.

Menacing or in memoriam, the Silent People and their meaning are left to interpretation.

Lithuania's outdoor sculpture trail of wooden folk art.

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

A botched 18th-century canal silenced one of Sweden's most magnificent waterfalls.

Gigantic natural towers in a Russian plateau.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

Monastery, army base, and infamous Soviet Gulag in the far Russian north.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

An auroral research program that superheats the ionosphere.

An abandoned town of skeletal wooden homes.

Monastery complex at the location where bodies of the executed Romanov royal family were discovered.

World's strongest whirlpool.

The convergence of two currents makes this a surprisingly pleasant getaway in the Arctic Circle.

Five mile wide circular ring of rock in the Russian Far East is a curious geological oddity.

Finnish lake, and scene of an infamous murder mystery.

A model village fit for an emperor.

Nightmarish example of the unintended consequences of weapons testing.

A phenomenal assembly of pueblos in New Mexico is the most complete example of ancient ruins north of the border.

Ancient human, animal, and geometric figures drawn in the earth.