Battle of Gettysburg:
Union casualties - 23,000
Confederate casualties - 28,000
World War 1, the Somme:
British casualties - 400,000 (57,470 the first day of battle)
French casualties - 200,000
German casualties - 450,000
World War 2, Savo Island
American and Australian casualties - 1,978 in 1 night
World War 2, Tarawa
American casualties - 3,301 in 4 days
World War 2, Saipan
American casualties - 16,660 in 25 days
Iraq War
American casualties - 9800 in 2 years, 10 months
