High Quality Content by WIKIPEDIA articles! The Alte Weser Lighthouse is located offshore from the estuary mouth of the river Weser in the German Bight, southern North Sea. It was built on sand between 1961 and 1964. The Alte Weser lighthouse took over duties and replaced the historical Roter Sand lighthouse on September 1, 1964. The latter had been built from 1883 to 1885.