On the cusp of the Great Depression, architect Hermann Soergel had a radical idea: Why not expand the landmass of Europe by draining part of the Mediterranean? It was all part of his plan to found the nation of Atlantropa.
Here you can see one of his plans for the dams that would be part of this geoengineering project. He'd also create canals in the Sahara Desert with the excess water.
Science historian and rare book afficionado John Ptak recently acquired a monograph where Soergel explains his grand scheme:
His most spectacular contribution-incubated in the mid-1920's and still clinging by its fingertips as an idea among some current thinkers-was to put a dam across the straights of Gibraltar. The dam would generate electricity of course, but most importantly to Soergel, it would also empty an enormous amount of water (lowering the sea by 200 metres) from the Mediterranean leaving vast new expanses of land to be developed and colonized over generations into the future. The water of course would have to go somewhere, and that somewhere was the Sahara Desert, somehow in its wake creating farmable and productive lands. Soergel was creating a certain, very wide, fantastical future of uncertain monumental prospects . . .
Some of Soergel's contemporaries got so excited by the idea that they started designing architecture for the new city, including the bridge you see above, which would have spanned the entire (drained) sea. Hey, if you can't colonize the countries bordering the Mediterranean anymore, why not colonize the sea itself?
Read the whole article on John Ptak's Science Books blog.