Earth Hour launched in Sydney in 2007 with backing from the city’s mayor. Inspired by this, San Francisco held "Lights Out" a few moths later. By 2008 there was participation from all continents with many landmark buildings around the world turning off non-essential lighting including the Sydney Opera House and the Empire State Building and participation has continued to increase year on year. In 2009, The United Nations observed Earth Hour at its Headquarters in New York and at other UN facilities around the world including the UN Environment Programme (UNEP) offices in Nairobi, Kenya.