The Tow­er of Her­cules Light­house, locat­ed at the entrance of La Coruña Har­bor in Gali­cia, Spain, has been in use since the late first cen­tu­ry AD. The only ful­ly pre­served Roman light­house that is still used for mar­itime sig­nal­ing, the Tow­er of Her­cules is a UNESCO World Her­itage site. The light­house was built on top of a 187-foot-tall rock jut­ting into the Atlantic Ocean. The light­house was restored and aug­ment­ed in the 18th cen­tu­ry.