port. By A.D. 400, the Roman Empire boasted some thirty lighthouses, most associated with specific ports, such as the Tour d'Ordre built by Caligula in A.D. 40 at Boulougne (then Gesoriacum) on the English Chan-nel in Gaul and the Caepio at Chiipiona, Spain, built in 20 B.C.

DOI link for port. By A.D. 400, the Roman Empire boasted some thirty lighthouses, most associated with specific ports, such as the Tour d'Ordre built by Caligula in A.D. 40 at Boulougne (then Gesoriacum) on the English Chan-nel in Gaul and the Caepio at Chiipiona, Spain, built in 20 B.C.

port. By A.D. 400, the Roman Empire boasted some thirty lighthouses, most associated with specific ports, such as the Tour d'Ordre built by Caligula in A.D. 40 at Boulougne (then Gesoriacum) on the English Chan-nel in Gaul and the Caepio at Chiipiona, Spain, built in 20 B.C.