In the 1550s, a series of floods of the Aare destroyed the valley floor villages of Balm and Bürglen, both of which were abandoned. The old village of Unterheid was destroyed in 1762 when the Aare changed its course, though the village was rebuilt in a new location. In 1734 the Alpbach wall was built to protect against the river, though this problem was not solved until the 1866–80 Aare water correction project.[1]