A tiny red pebble marks what may be the quietest outdoor spot in the United States.

The longest continuous lava tube in Oregon.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

Walk in the footsteps of the gods and straddle two tectonic plates.

Iceland's largest geothermal mud pool is a little bit haunted and a little bit dangerous.

Sweden's southernmost prehistoric rock art is hidden just outside Gothenburg.

Three columns of volcanic rock shoot out of the ocean.

A two-inch thick solid brass rod that extends an astounding one kilometer straight into the earth.

The Goose Girl of Göttingen, Germany might well be the most kissed girl in the world.

Home to the world’s oldest seismograph and a four-ton steel ball that makes its own earthquakes.

The man who gave his name to magnetic measurement is buried in the city where he did his best work.

What was once thought to be a wellspring of unicorn bones is actually just a prehistoric burial site.

This historic stone bridge has an entire neighborhood clinging to its sides.

Made from trees and then abandoned, this fence is still growing along a path in Germany.

At this unusual park, domes, ladders, chairs, and more are made from trees.

A tiny chapel clings to a precipice above Germany’s gemstone capital.

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.

Once the local rulers had gone these enchanting ruins housed common folk in an almost real life fairy tale.

This 600-year-old home seems to defy physics.

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

This tri-part waterfall is a little bit of fairytale beauty in the heart of Luxembourg's Little Switzerland.

This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

This Luxembourg cave is covered in cryptic looking marks left by mining activity.