The celebration of the Alki Lighthouse centennial, which takes place all summer long in 2013, is described in this video taken at Alki Point and narrated by Clay Eals, executive director of the Southwest Seattle Historical Society. Weekend tours are under way at the lighthouse (1 to 4 p.m.), and an expanded exhibit on the lighthouse is open at the historical society’s Log House Museum, including rare artifacts, photos and children’s activities (noon to 4 p.m. Thursday through Sunday).