<i>&gt; Short of mapping the lake bottom, which is unrealistic</i><p>Is it? <a href="http:&#x2F;&#x2F;www.telegraph.co.uk&#x2F;news&#x2F;earth&#x2F;environment&#x2F;archaeology&#x2F;11836627&#x2F;British-Atlantis-archaeologists-begin-exploring-lost-world-of-Doggerland.html" rel="nofollow">http:&#x2F;&#x2F;www.telegraph.co.uk&#x2F;news&#x2F;earth&#x2F;environment&#x2F;archaeolog...</a><p>Granted, these guys seem to be piggybacking on massive work done by oil companies, but the North Sea is roughly 3x Lake Superior, so you only need 1&#x2F;3 of the effort. You just have to find an excuse...