Landsort lighthouse tower was built in 1689, with an upper conical iron section added in 1870. Open fires have been lit here since a long time ago. The first 'real' lighthouse was lit in 1651 and, until the now-standing tower was built, a couple of different buildings were used as the lighthouse. The 1689 tower was constructed to carry an open fire which ran on coal. In 1840, a colza oil lamp was installed. The flame ran on paraffin from 1887, and in 1938 it was electrified. Today the Swedish Maritime Administration owns and runs the lighthouse.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.