South Stack lighthouse on Anglesey island recently marked its 21st decade of operation, having warned passing ships of the rocks below since its completion in 1809. The main light is visible to passing vessels on the Irish sea for 24 miles, and was designed to allow safe passage for ships on the treacherous Dublin–Holyhead–Liverpool sea route, acting as the first beacon along the northern coast of Wales for east-bound ships to England. It was designed by Daniel Alexander, surveyor to Trinity House aka the mothership of Britain's lighthouses in London, which now controls South Stack remotely via the wonders of modern technology from 278 miles away.