The Blitz had a devastating effect on the Society's Northumberland Avenue headquarters and Library. On the night of 16/17 April 1941 the building was struck by a two-ton bomb. Seventy-four people were present at the time; one member was killed and another injured, and two members of staff badly hurt. Fire ignited by the blast and the large quantity of water pumped in to extinguish it meant some unique collections were destroyed; examples, painstakingly assembled over more than seventy years, included: the Library of Overseas Law, the contents of the Newspaper Room, and sections covering the general British Empire, foreign colonies, the First World War, Malta and Gibraltar. The lost collections on the German colonial empire, the French colonial empire, the Dutch Empire, the Italian Empire, and Belgian overseas colonies - mainly in foreign languages and published overseas - were unique in the United Kingdom. Numerous early accounts of exploration, voyages and travel were likewise destroyed. Out of a collection of 260,000, total losses were estimated at approximately 35,000 books and 5,000 pamphlets. On the night of 10/11 May 1941, the hardest night of the Blitz, the Northumberland Avenue address was again severely damaged.