the desert was prophecy enough

Heicheng, the largest and best preserved ancient city site along the Silk Road that linked China with Central and Western Asia, is being devoured by flowing sand.

from: Ancient city site in Inner Mongolia jeopardized by sand

V., chapter III, section V:

The only Mahdi is the desert. Mohammed Ahmed, the Madhi of '83, was believed by some to be sleeping not dead in a cavern near Baghdad. And on the Last Day, when the prophet Christ re-establishes el-Islam as the religion of the world he will return to life to slay Dejal the antichrist at a church gate somewhere in Palestine. The Angel Asrafil will trumpet a blast to kill everything on earth, and another to awaken the dead. But the desert's angel had hidden all the trumpets beneath the sand. The desert was prophecy enough of the Last Day.