A concrete caisson or 'Phoenix', part of the Mulberry artificial harbour for D-Day, under construction, 27 January 1944. H35379

A concrete caisson or 'Phoenix', part of the Mulberry artificial harbour for D-Day, under construction, 27 January 1944.
Construction in Britain: An early stage in the construction of a large concrete caisson, known as a Phoenix. The Phoenix units were fitted with flooding valves to allow sinking on site to form a breakwater.