Tŵr Mawr Lighthouse, Ynys Llanddwyn, Anglesey, Wales (© Lukas Bischoff/Getty Images)

At the far edge of Ynys Llanddwyn, where the land quietly gives way to sea, Tŵr Mawr Lighthouse stands watch without making a fuss. It is not tall, not flashy, but it knows its purpose—and it keeps it bright.