Hundreds of millions of sinkholes exist on our planet, and more appear every day. They form in the deepest, darkest forests in Germany, on the steaming plains of Zambia, in the thick jungles of Belize, and on the steep mountains of Puerto Rico. They appear in the wilds of Vietnam and Laos, in the African Congo, and in the high mountains of Yugoslavia. Sinkholes hide in the Nullabor Plain of Australia, the wind-swept Arabian Desert, and the islands of the Mediterranean Sea. They drop through fossilized coral reef terraces in Japan. They appear in cold, snowy places too: on the outskirts of Moscow and in the Alaskan tundra. Sinkholes are even found in the ocean floor.

The United States has millions of sinkholes. Almost 75% of the continental United States has the right geology for sinkholes of one type or another to appear. These sinkholes lurk everywhere. You’ll find them in the deserts of southern California, along the Pecos River in New Mexico, in the prairies of the Midwest, and in the pine forests of Maine, creating problems for land developers but unique opportunities for new ecological communities to develop.