Trwyn Du Lighthouse, also known as Penmon Lighthouse, is a lighthouse between Black Point near Penmon and Ynys Seiriol, or Puffin Island, at the eastern extremity of Anglesey, marking the passage between the two islands.The tower is distinguished by its original three black bands painted on a white background. Its also bears the words "NO PASSAGE LANDWARD" on its north and south sides.In 1922 Trwyn Du became the first Trinity House lighthouse to be automated