Our understanding of Atlantis is primarily based on the work of Plato. Plato recounts a story told to Solon about the history of Atlantis and its destruction. Plato is adamant that this is not a myth, but a real story
and what is this ancient famous action of which Critias spoke, not as a mere legend, but as a veritable action of the Athenian State, which Solon recounted!
In this story, Solon goes to visit Egypt. There he meets a priest who tells him about Atlantis. The story says that Atlantis sunk under the waves in a single day and night. It also says that this event occurred 9000 years before.
Solon lived from 638 BC to 558 BC. This means that the destruction of Atlantis would have occurred around 11,600 years ago.
Recently, scientific research has confirmed that there was a large flooding event at almost this exact point in time:
We propose that MWP‐1B is the direct albeit lagged response of the Northern Hemisphere ice sheets to the rapid warming marking the end of the Younger Dryas coinciding with rapid warming in the circum‐North Atlantic region and the polar front shift from its zonal to meridional position 11.65 kyr B.P. As predicted by glaciological models, the ice sheet response to rapid North Atlantic warming was lagged by 400 years due to the thermal inertia of large ice sheets.
In other words, there was a large influx of water from melting ice caps that occurred 11,650 years ago. Which is pretty much exactly when Plato says that Atlantis sunk under the waves.
Now, how is it that Atlantis suddenly sunk under the waves? There are different theories. One theory is that the melting during this time period (called the Younger Dryas) was caused by one or more comets. Another theory is that water built up inside of the glaciers and burst, sending a large pulse of water. There is evidence of these pulses all over North America:
Although researchers have suggested a cosmic impact might have set off this Big Freeze, the prevailing theory for the cause of the Younger Dryas was a vast pulse of freshwater— a greater volume than all of North America’s Great Lakes combined — that poured into the Atlantic and Arctic Oceans. The source of this flood was apparently the glacial Lake Agassiz, located along the southern margin of the Laurentide Ice Sheet, which at its maximum 21,000 years ago was 6,500 to 9,800 feet (2,000 to 3,000 meters) thick and covered much of North America, from the Arctic Ocean south to Seattle and New York.
“The flood was likely caused by the sudden breaking of an ice dam,” said researcher Alan Condron, a physical oceanographer at the University of Massachusetts at Amherst. “Prior to the flood, meltwater is thought to have drained into the Gulf of Mexico, down the Mississippi River. After the dam broke, the water rapidly flowed into the ocean via a different river drainage system.”
To make a long story short, Plato’s story of an ancient civilization sinking under the seas is strongly supported by recent scientific discoveries.