Tour the inside of a massive lava tube formed during a 1949 volcanic eruption.

A rocky face gazes out over an enormous volcanic crater.

This replica of Columbus's famous ship houses the history of La Palma's maritime importance during the Age of Exploration.

Indigenous cultures believed all life would end if this enormous rock toppled.

This unique rock formation is quite the local celebrity, although one day it may come crashing down.

Lava stone structures possibly dating back to the 19th century may have been a stopping point for voyagers between ancient Egypt and the Mayan Civilization.

Behind this pair of dragon trees, there is a tragic story of lost love.

The largest salt farm in the Canary Islands is located at the foot of an active volcano.

These wooden balconies that are both decorative and functional.

This local emblem is the oldest and largest dragon tree in the Canary Islands.

According to the Guanches, the aboriginal people of the Canary Islands, the king of evil lives inside this volcano.

An unexpected ghost village lurks on the southeast coast of Tenerife.

On La Gomera, "Silbadors" communicate in a 4,000-word language of whistles.

You can soak in three relaxing pools filled daily by the tide.

Teeny tiny hotel on the coast of the Canary Islands.

Volcanic rocks ground down into sand make this Spanish beach as black as night.

A pre-Hispanic pyramid in the middle of a tourist district in the Canary Islands.

The chefs at El Diablo use heat generated by an active volcano to cook the food.

The ceiling of Prohodna Cave in northern Bulgaria affords a peek at the sky via two deity-sized-eye-shaped holes.

Made famous by "Star Wars," these troglodyte homes face an uncertain future.

The best-preserved Roman small town in North Africa.

A seemingly simple canyon that was the backdrop to a number of famous movies.

The largest and best-preserved Roman amphitheater in Africa was designed to seat 35,000 people.

Founded in 670, this ancient mosque is an architectural time portal.