Watch: Horseshoe Falls transform in the Yosemite National Park

Photographers from the world have flocked to Yosemite National Park in California this week for the renowned "Firefall."

While pictures look as if glowing hot lava is spilling over the top of the vertical rock formation known as El Capitan, the rare event is actually caused when the setting sun is reflected off Horsetail Falls.

This phenomenon occures  in mid-February every year.

Horseshoe Falls in Yosemite – when captured with the right flow, at the right time and in the right light – changes so that the water glows yellow, orange and red, often looking like 1,570 feet of falling fire which lasts about 10 minutes.