Much of the water on Terra Nova is subterranean. The MacAllen network of caves contains most of it, and is nearly a worldwide phenomenon. Natural artesian springs appear all over the globe, even occasionally in the deep deserts of the Badlands. Most of the network is deep underground, often thousands of feet below the surface. Even whole ecosystems of life exist in some of the airless and perpetually dark areas of the network. The extent of the cave system is unknown.