Barragem do Alqueva
If the valleys surrounding Monsaraz look flooded, that's because they are. In the late 1990s, Portugal and Spain jointly began work on a huge dam that created the 250-square-km (96-square-mile) Alqueva Reservoir, Europe's largest lake. You can drive or walk across the dam, but one of the best ways to see the lake's expanse is by boat. Visit the nearby town of Amieira, where the Amieira Marina offers day trips on the lake, boat rentals, and dining at a waterfront restaurant.
