The Mediterranean sea was once dry land, flooded when the Atlantic broke through the bridge of land that became the strait of Gibraltar. But that's not to say we lost a green and pleasant world to the waters: the Med had been open ocean before, had only dried out when that land bridge formed in the first place, and was refilled in a matter of months in the deluge.
It was salt.
Lots and lots of salt.
More salt than you're capable of believing, I'll bet.
Some of these layers of salt were two miles thick. As National Geographic science writer Maya Wei-Haas puts it: "enough to give each of the world's 7.7 billion people nearly 50 Great Pyramids of Giza filled with the stuff." … An enormous salty dryness, up to 900 miles across, with sloping cliffs over a mile deep – shallower in the west of the Mediterranean bowl where the seabed is former of continental crust, much deeper in the east (and at its extreme eastern end, an incredible "Egyptian Grand Canyon," formed from the foundations of the Nile)…
Enough halite to build everyone on earth 50 pyramids, yet a decent sheet of plywood is $65!
Every second, around 2,400 cubic metres of water tumble over Niagara Falls, representing a total weight of around 3,100 tons, which pounds the base of the waterfall with a force of 2,509 tons. That's every second, remember…. In contrast, the flood Garcia-Castellanos and his team were modelling seemed to require a peak flow of a hundred million cubic metres of water a second.
So, Roland, here's the pitch: the flood comes and someone who has lost everything in the initial dam collapse has to rush ahead of the deluge over the flats to warn all the folks living in peace and harmony at the east end of the vast salty basin, at the freshwater paradise base of the enormous Nile waterfalls. Yeah, sure, aliens show up, whatever.