The lighthouse featured in today's image stands in southern Portugal's popular Algarve region. Built in 1919, Alfanzina Lighthouse helps ships navigate dangerous waters near the town of Carvoeiro. A popular tourist destination, the lighthouse also has become a symbol of the region's deep links to the sea. If you're lucky enough to live near a lighthouse, this weekend is the perfect time to pay it a visit.

Today marks the start of International Lighthouse and Lightship Weekend, celebrating this vital maritime infrastructure. Originally, lighthouses were powered by fires and oil lamps, requiring lighthouse keepers to maintain them. These days, however, most lighthouses have been automated and installed with electric light sources. In waters that are too deep or otherwise unsuitable to build a lighthouse, lightships—moored vessels outfitted with beacon lights—have often been used.