Google doodle in Earth Day 2013

Mountain View, California April 22 – This is Google's 13th Earth Day doodle. Today's elaborate animation shows the cycle of seasons represented by the rising and falling sun and moon. Users can play and pause the moon and sun on four different images.

Earth Day is held every year on 22 April to highlight environmental issues, with events held around the world to show support. More than one billion people across 192 countries now
participate in activities, with planting trees being one of the most popular ways to show support.

US senator Gaylord Nelson conceived the idea for the event in the wake of the 1969 oil spill in Santa Barbara, California. The first Earth Day began in 1970 when 20 million Americans took to the streets to demand a sustainable environment and it is widely credited with launching the modern environmental movement.

The first event led to the creation of the US Environmental Protection Agency and the passage of the Clean Air, Clean Water and Endangered Species Act.