Bonneville Lock and Dam was built from 1933-38 to provide hydroelectric power as well as improve inland navigation on the Columbia River. The dam is part of a series of dams and locks that allow barges to navigate over 400 miles inland from the Pacific Ocean up to Lewiston, ID. A highlight at the visitor center are the fish ladders with interactive exhibits related to salmon migration. Timing of initial visit was too early in the season to see fish activity in the ladders - will need to stop by again in the summer months.