Boondoggles Are Us: Marketing Continental Prison Walls As Weather Protection

"Building three "Great Walls" across Tornado Alley in the US could eliminate the disasters, a physicist says. The barriers - 300m (980ft) high and up to 100 miles long - would act like hill ranges, softening winds before twisters can form. They would cost $16bn (£9.6bn) to build but save billions of dollars of damage each year, said Prof Rongjia Tao, of Temple University, Philadelphia."