President Franklin D. Roosevelt dedicated the first federal dam to span the Columbia in 1937. Its generators (visible from a balcony on a self-guided tour or up close during free guided tours offered daily in summer and on weekends the rest of the year) have a capacity of more than a million kilowatts, enough to supply power to more than 200,000 single-family homes. There's an extensive visitor center on Bradford Island, complete with underwater windows where gaggles of kids watch migrating salmon and steelhead as they struggle up fish ladders. The best viewing times are between April and October. In recent years the dwindling runs of wild Columbia salmon have made the dam a subject of much environmental controversy.
Exit 40 from I–84, follow signs 1 mile to visitor center, Cascade Locks, Oregon, 97014, United States