The World's Greatest Geological Wonders: 36 Spectacular Sites

Wysession's criteria for choosing more than 200 different geologic wonders in nearly 120 countries; the first on his list is the beautiful Greek island of Santorini; the relic of a volcanic eruption; an effect on the ancient Mediterranean world.

Moving to volcanoes; Mount Fuji in Japan is a sacred site whose nearly perfect cone shape is a popular subject in Japanese art; the origin of volcanoes such as Mount Fuji; the special conditions that produce their sturdy symmetrical cones.

Phenomena associated with plate tectonics; the Galapagos Islands are made famous by Charles Darwin; this island is on a volcanic hotspot near a mid-ocean ridge, formed by moving tectonic plates; natural wonders abound, both above and below water.

The African Rift Valley is a mid-ocean ridge in the making; from the Red Sea to Mount Kilimanjaro, tectonic forces split Africa apart, forming a new ocean in the process; this valley is also the site of fossil discoveries relating to early humans.

A striking feature of the African Rift Valley is the lava lake at Erta Ale in Ethiopia; this seething cauldron of molten rock is the oldest of the world's five active lava lakes; it replicates on a small scale the complex process of plate tectonics.

The evolution of life is revealed in the rare fossils of the Burgess Shale in British Columbia; this mountainside quarry records the proliferation of new organisms, both familiar and bizarre, that follow a mass extinction half a billion years ago.