What was the biggest (tallest) sand dune ever recorded..?

Question

and when it was recorded

Answer 1

The biggest sand dunes are in Algeria in the Sahara Desert. They are up to 430m (1,411 ft) high, nearly three times the height of the Greatest Pyramid of Cheops in Egypt or nearly or twice as high as Canary Wharf.

Answer 2

http://en.wikipedia.org/wiki/Dune#World....