On the beach between Bognor Regis and Aldwick lies the wreck of a Floating Pontoon which was intended to form part of the Mulberry Floating Harbours used by the Allies to support the invasion of France on D-Day 6 June 1944.  As part of the preparations, a number of sections of harbour were moored, partly submerged to avoid detection, off the West Sussex coast, prior to being towed across the Channel. This particular section, a "beetle" pontoon, and intended to form part of a roadway, broke free during a storm on 4 June 1944, the day before it was due to go over the channel to Arromanches. This section was considered unrecoverable and was abandoned. It failed to make it across the Channel.  It was washed up on the beach shortly after D-Day and to this day is clearly visible at low tide throughout the year.

This important relic is located about 500 yards West of  the beach huts at Fish Lane, Aldwick, Bognor Regis.  It lies about 100 metres offshore and is easily accessible at low tide. 

It wasn't the only unit to break free, a "caisson" pontoon lies nearby off the coast  between Pagham and Selsey. Lying in about 10 metres of water, its a popular scuba diving site.  
In 2017 it was reported that the carcass of a further pontoon had been uncovered  by tidal scouring a mile or so to the west at Pagham Harbour.