A thousand years ago, rice farmers in Bali created a complex, ritual-based farming system in which "subaks," self-governing, democratic organizations of farmers, managed the shared use of irrigation water among terraced rice paddies. Subak heads met in sacred temples, stationed along irrigation pathways, to coordinate planting and watering schedules in ways that would ensure an ecologically responsible sharing of resources. Although it has faced challenges, Bali's ancient water temple system remains largely in place today. Hundreds of water temples are sites of festivals, rituals and religious offerings, thanking the gods for the gift of irrigation water, which flows through canals and tunnels from Bali's volcanic Lake Batur into numerous rivers and streams and to the jewel-like terraced fields. This system is considered a living model of sustainability.