It naturally happened about 6-7 million years ago when the Straight of Gibraltar was naturally dammed then reconnected. It took an estimated 10,000 years to ref

It naturally happened about 6-7 million years ago when the Straight of Gibraltar was naturally dammed then reconnected. It took an estimated 10,000 years to refill the Mediterranean. [0] From that we do know that it's probably not the best plan though. The water in the Med would become even saltier and might eventually completely stop supporting life. [0] https://en.wikipedia.org/wiki/Zanclean_flood https://en.wikipedia.org/wiki/Zanclean_flood