Tower of Hercules, A Coruña, Spain

The Roman lighthouse above A Coruña in Galicia, built around the end of the 1st century or start of the 2nd, and still marking the harbor entrance today. The squared stone casing and lantern date from an 18th-century restoration that wrapped the Roman core rather than replacing it, which is why the tower looks younger than it is. A UNESCO World Heritage Site since 2009, it is the only Roman lighthouse still working, and the headland walk around it is the best way to see it.