The Mississippi Basin Model reproduces the drainage basin of the Mississippi River at a horizontal scale of 1:2000 and a vertical scale of 1:100. This makes it the largest small-scale working model in the world¹!

The concrete model was built by the Army Corps of Engineers in the 1940s, and initial earthwork was carried out by German POWs. It was eventually completed in 1966.

By the 1980s the model was superseded by computer modelling techniques, but it was widely agreed that the model had been a success: helping to solve numerous flood-control problems and thus saving lives.

Thanks to Ned Mitchell.