The Régua Dam is one of five hydroelectric dams that turn the lower Douro into a navigable sequence of long calm reaches. Opened in 1973, the dam has a single shipping lock that handles all the cruise traffic moving up and down the river — the lock chamber is a popular point to stop and watch from the bank.
This is not a tourist attraction in the conventional sense, but if you are interested in how the Douro became navigable for tourism — only since the dam programme of the 20th century — the Régua Dam is the easiest one to visit, and a useful waypoint on the drive between Régua and Lamego.