In 2011, the foundation launched a program called "Reinvent the Toilet Challenge" with the aim to promote the development of innovations in toilet design to benefit the 2.5 billion people that do not have access to safe and effective sanitation. This program has generated significant interest of the mainstream media. It was complemented by a program called "Grand Challenges Explorations" (2011 to 2013 with some follow-up grants reaching until 2015) which involved grants of US$100,000 each in the first round. Both funding schemes explicitly excluded project ideas that relied on centralized sewerage systems or are not compatible with development country contexts.