Following a viewing of a compilation film of archive footage, we walked around the large central room to examine each panel of the Overlord Tapestry in sequence. The work that went into it is stunning, and the details of each of the main political players from the US and UK make them instantly recognisable rendered in fabric and silks.
The other half of the museum shows not only the details of the D-Day landings but also how the people of Portsmouth were affected by the War in general. Plus there were more archive films, although I only had time to watch one about the women of the RAF (which sadly overlooked the delivery pilots that I'm really interested in).
Well worth a visit.