Freund, a University of Hartford professor, believes he and his research team have found the legendary island-city described by Plato in about 360 B.C. as having "in a single day and night ... disappeared into the depths of the sea."
Using satellite photography, ground-penetrating radar, underwater technology and some old-fashioned reasoning, Freund said his team pinpointed the city in a vast marsh in southern Spain that dries out one month a year. Their findings are featured in a National Geographic special premiering tonight, "Finding Atlantis."
His team's search began in 2008 with a space satellite photograph showing what looked to be a submerged city in Spain's Dona Ana Park. In 2009 and 2010, Freund's researchers worked with Spanish archaeologists and geologists to explore beneath the mud flats using radar and imaging.
The discovery was clinched, Freund said, with the later find of "standing stones" and a series of memorial cities in central Spain built in the image of Atlantis.
"We found something that no one else has ever seen before, which gives it a layer of credibility, especially for archaeology, that makes a lot more sense," Freund told Reuters.
The memorial sites are significant to Freund's theory because refugees from the lost city would have built smaller-scale versions in tribute. And so when a Spanish scientist led him to ancient sites surrounded by concentric moats -- and a museum featuring standing stones with a symbol similar to Plato's drawing of Atlantis -- Freund was convinced these were commemorations of the destroyed city.
"There are more than 100 of them, and they come from all different places in the area," Freund told AOL's local news site Canton Patch.
"In crime, you follow the money," he told Patch. "In archaeology, you follow the stones."
His team also found ancient wood dating back to 440 B.C. A core sample taken at the marsh showed a layer of methane -- an indication to Freund that a lot of living things all died at once.
Explorers looking for Atlantis previously have focused on the Mediterranean Sea as well as the Atlantic, Pacific and Indian oceans. The lost city has been "found" many times over the years, including by Russian scientists who pinpointed a ruined town in the Black Sea; an American who found man-made walls a mile deep in the Mediterranean; and Swedish researchers who found it in the North Sea.
The lost city even was proclaimed found when people searching Google Earth spotted lines resembling a city street grid in the ocean off the coast of Africa. Google squelched the revelation when it explained the lines actually were left by a boat collecting data.
Researchers plan more excavations at the Spanish site, and Freund agreed his current findings won't put a definitive end to the debate.
"It's never like finding the Titanic. It's never like finding Tutankhamun's tomb. That's the way, in the best of all circumstances, that you find something intact," Freund told the Courant.
"You'll not be able to convince all the people all the time," he said.