Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

The Acropolis of this little-visited Mayan archaeological site offers great views of Chiapas’s Lake District.

This series of waterfalls tumble into a radiantly blue river.

Tubing through a cave lit with glowworms is a magical underground experience.

Millions of glowing microscopic organisms light up the waters of this luminous lagoon.

Once the path of a railway tunnel, now home to thousands of glowing insects.

Bioluminescence in the reefs of the Maldives causes the sea to glow like a starry night sky.

A galaxy of glowworms—larvae of a gnat—hides deep in the belly of these caves.

An abandoned railroad tunnel is now filled with bioluminescent bugs.

This is the house that spite built.

Two volcanic lakes in an enormous crater formed in a prehistoric eruption.

Three million year old fossils are exposed for all to see on this Icelandic shore.

Instead of solid circles, the stoplights in this northern Icelandic town have glowing red hearts.

A little-visited waterfall in an otherworldly landscape.

This tumultuous Icelandic lava field looks so alien European researchers want to use it as a stand-in for Mars.

These ominous lava formations were said to be an entrance to the netherworld so of course they inspired a famous metal band.

This elegant arc of a waterfall marks a religious turning point.

The most powerful waterfall in all of Europe.

An ornate "graveyard" for some of the country's forlorn building relics.

A honeycomb-like structure of interlocking shelves creates a beehive of books.

The oldest county library in the United States.

This unassuming bookstore in the heart of Madrid is one of the oldest in Spain.

This alley off Edinburgh's Royal Mile contains remnants of the city's seedier history.

The ominously named cave is home to some remarkable ancient art.