4 ms·Probably from http://en.wikipedia.org/wiki/Rub'_al_Khali http://en.wikipedia.org/wiki/Rub'_al_Khaliby _ihaque 12y agoProbably from http://en.wikipedia.org/wiki/Rub'_al_Khali http://en.wikipedia.org/wiki/Rub'_al_Khali