Todays Update to the EXTREME SERIES :

Isaouane-n-Tifernine, Algeria : Highest Sand Dunes on the Earth

The world's highest measured sand dunes are those in the Saharan sand sea of Isaouane-n-Tifernine in east-central Algeria. They have a wavelength of 5 km (3 miles) and attain a height of 465 m (1,526 ft).