Apollonian gasket in Black Rock Desert in Nevada

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http://jimdenevan.com/news.htm

Big enough to contain over 176 Wembley Stadiums, the giant drawing by Jim Denevan is visible from 40,000 feet up in the sky.

Taking 15 days to complete, Mr Denevan and a team of three colleagues worked day and night on the stunning piece in May of this year, which has a diameter of just over three miles.

http://www.telegraph.co.uk/culture/art/art-news/6824326/Sand-drawing-the-worlds-largest-single-artwork.html