Abu Hurairah (May Allah be pleased with him) said

The Messenger of Allah (ﷺ) said, "The Hour will not come to pass before the River Euphrates dries up to unveil the mountain of gold, for which people will fight. Ninety-nine out of one hundred will die (in the fighting) and every man amongst them will say: 'Perhaps I may be the only one to remain alive."'

Another narration is: "The time is near when the River Euphrates will dry up to unveil a treasure of gold. Whosoever may be alive at that time, should not take anything of it."

[Al-Bukhari and Muslim]