Perspective view taken from La ville de Boulogne-sur-mer 1611, drawn by Joachim Duvient. This 12-stories tower, also called Caligula Lighthouse, was 65 meters high. Built in the first century AD, lt fell down in 1644.

1	Pierre Daudry, FAMILLES ANCIENNES DU BOULONNAIS, volume 1, page 434. Editions des Beffrois, Dunkerque,1983.