Enchanting cave with a river crashing through the roof.

The Andean town where every single building is decorated with a brightly colored frieze.

The highest pedestrian bridge in Singapore looks like a series of undulating waves rising between two public parks.

Thousands of flowers create enchanting pink tunnels over the city streets.

Located outside Medellín, this Colombian park focuses on conservation and sustainability.

The highest point in Virginia can only be reached by passing through ponies and flowers.

An eerie and beautiful group of columns mark the site of a grand mansion lost to time and fire.

Watch the newest land on the planet form before your eyes.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Stroll through a wonderland of stupendous moss-covered trees.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

A DIY art gallery/music venue/lecture hall dedicated to video game culture.

A hands-on traveling collection of the innovative devices of yesteryear.

Dr. Strangelove-esque tours reveal the inside a bunker once reserved for Stalin himself.

Near Birmingham, England three and a half miles of top-secret tunnels housed a World War II “shadow factory” and a Cold War nuclear bunker.

A serene desert oasis speckled with ancient artifacts.

Amazing pre-Civil War ruins alongside a shallow, rocky river that hosts beautiful (but endangered) lilies.

Follow the path behind this treat-slinging camper van to a sculpture garden in the forest.

Rare videos and memorabilia await visitors inside this unique store.

This river island in Sierra Leone is home to impressive biodiversity and the country's first community conservation program.