American mural artist Robert Wyland began on Tuesday to create the world's largest painting of the planet on the rooftop of a California arena in recognition of the Earth Day.

The image of the planet will be painted over a 24-hour period on the 12,000-square-meter rooftop of the Long Beach Arena, and complement "Planet Ocean," the world's largest mural painted on the arena's exterior walls also by the same artist.

Wyland, who is known for painting large, outdoor murals of whales and other ocean life, said the image will be visible on Google Earth.

The mural is expected to be unveiled at 10:00 AM on Wednesday in recognition of the Earth Day, according to the Long Beach Convention and Visitors Bureau.

The annual Earth Day, which falls on April 22, is celebrated around the world to inspire awareness and appreciation for the Earth's environment. The event was founded by US Senator Gaylord Nelson in 1970.