although the Straights of Gibraltor are referred to as the Pillars of Hercules, there are also several sites in the eastern Med that are similarly named. Plato's Egyptian sources are far more likely to be referring to one of those sites than the Straights, as they dealt with them far more frequently.
I personally hold with the theory that Atlantis was the volcanic island of Thera (modern Greek island of Santorini), fairly near to Cyprus. Several analysts have pointed out that the Egyptian "900" was often mis-translated in Greek as 9,000, which is how many years back (from his time) Plato placed the events of the destruction of Atlantis. If we look at 900 years instead of 9,000 they end up with the approximate date of the massive explosion of the island of Thera (bigger than Krakatoa or Mt St Helens, by a long shot). Prior to its destruction it would have had the appropriate physical characteristics to match Atlantis. At least the physical location descriptions would match close enough with Crete to satisfy the same "criteria" sited by the author to support the notion of the nearby Cyprus. This theory also accounts for the destruction of the Minoan (Crete) culture at around the same time. some even hold that it coincides with the "pillar of fire" and the parting of the Red Sea from Exodus. Certainly it was a big event, but to be recorded in such disparate sources does cause me some problems.
The big problem I have with this guys theory is that, so far as I've been able to find out, the breaching of the dam (represented at one end by the Rock of Gibralter) between the Atlantic and the Med happened around 65 million years ago. I don't think there were too many human civalizations, high or low, around that time. It certainly doesn't jibe with Platos account of 9,000 years either, though factoring in ice ages may fix that problem, though not with the "dam breach," but with the sea level changes, as suggested by another poster.
The Thera/Santorini explosion has been dated to 1628BC, that's why I argue for an earlier date for the Exodus. Charred grain under the crumpled wall of Jerico are just on top of the Santorini ash layer. The Santorini volcano was a worldwide event as it is recorded worldwide by tree rings...as well as the Ice Cores.
The Mediterranean completely dried out 4-5 million years ago which would necessitate that the passage at Gilbralter was blocked at that time.