As the rainfall decreased, many of the cities farther away from Lake Titicaca began to tender fewer foodstuffs to the elites. As the surplus of food decreased, and thus the amount available to underpin their power, the control of the elites began to falter. The capital city became the last place viable for food production due to the resiliency of the raised field method of agriculture. Tiwanaku disappeared around AD 1000 because food production, the main source of the elites' power, dried up. The area remained uninhabited for centuries thereafter.