Editor's Choice: Bay Model helped urban planning

The Bay Model, a replica of the San Francisco Bay and Sacramento-San Joaquin Delta, was built in 1956 to help scientists study various environmental impacts on the bay before computer modeling. The country's largest working hydraulic model is made of 286 one-ton slabs of concrete. It has representations of all six bridges and a computerized hydraulic system that controls the waterworks. The model is on display in Sausalito.