Salam Aleikum,

They lived where today there is The Gulf. Before it was filled with water it was a valley with living conditions where Noah and his nation lived.

Lost Civilization May Have Existed Beneath the Persian Gulf

At its peak, the floodplain now below the Gulf would have been about the size of Great Britain, and then shrank as water began to flood the area. Then, about 8,000 years ago, the land would have been swallowed up by the Indian Ocean, the review scientist said.

The Gulf Oasis would have been a shallow inland basin exposed from about 75,000 years ago until 8,000 years ago, forming the southern tip of the Fertile Crescent, according to historical sea-level records.

And it would have been an ideal refuge from the harsh deserts surrounding it, with fresh water supplied by the Tigris, Euphrates, Karun and Wadi Baton Rivers, as well as by upwelling springs, Rose said. And during the last ice age when conditions were at their driest, this basin would've been at its largest.
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When Noah survived, his ark landed at the territory which is today South Iraq, where the Sumerian civilisation was and this is why the Sumerians were so advanced.