Intensely colorful calcite pools in Southern China.

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

Nature's slip and slide.

A Maori village obliterated by an 1886 volcanic eruption.

The once and future home of New Zealand's famed Pink and White Terraces.

Deadly scalding and one of the largest hot springs in the world.

This unusual rock formation looks like an apple that has been neatly sliced in half.

The bluer than blue waters in these natural Israeli caves are reached via the world's steepest cable car.

The water here is so clear you can see the mysteriously sunken ship from the surface.

What is left of the pillar of Saint Simeon, the voluntary martyr who climbed the column to give his sermons, remaining perched there for thirty-seven years.

Mausoleum and Holy Seat of Antiochus I of Commagene.

Naturally protected city carved from a rock face.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

While not Turkey's deepest underground city, this subterranean redoubt is the largest.

Live a night as a Byzantine King, with a minibar and private jacuzzi.

This ancient subterranean megalopolis is known for the hot oil traps that were installed above each of its entrances.

Visit this odd display of indigenous style in Argentine wine country.

105-foot wide giant metallic flower blooms anew every day in the heart of Buenos Aires.

This historic, palatial theater is now one of the world’s most beautiful bookstores.

A vibrant street away from the typical tourist track, lined with colorful, mosaic-covered houses.

Xul Solar was an artist of alternate worlds, inventor of languages, and dreamer of utopias.

This giant power line tower is a robot that can express its moods in neon.

A retiree's challenge to build an outdoor wonderland out of trash.