What were black out curtains?

Blackout Curtains were a feature of The Blackout - the tactics of blocking out all lights at night during the Second World War, so that enemy bomber planes could not identify targets.

Blackout Curtains were made of heavy black serge or blanket material, and the idea was to completely remove any flashes or 'chinks' of light from inside the house. Street lights and traffic lights (and lights on cars and buses) were also strictly forbidden during The Blackout. This resulted in a number of road accidents and injuries.

On the whole the measures were effective. German bomber pilots reported difficulty identifying specific areas of cities such as Manchester and Liverpool because of The Blackout, and in the case of Hull, the East Park boating lake was bombed as the Germans believed it to be part of Hull Docks.