Two 'leading light' towers (High and Low), built 1817-19 and designed by Robert Stevenson, stood 560 feet apart on the Calf of Man to guide ships clear of the Chicken Rock hazard a mile offshore. Both were discontinued in January 1875 when Chicken Rock Lighthouse took over the role. A new manned lighthouse — the last manned lighthouse built by the Northern Lighthouse Board — was constructed between the old towers in 1968, automated in 1995, and finally discontinued in 2007 when Chicken Rock was restored as the primary light.