On June 6, 1944, Allied soldiers stormed the beaches of Normandy in northern France in the operation known as D-Day. More than 150,000 troops took part in the largest seaborne invasion in history, which marked a turning point in the war. Ahead of the 70th anniversary of D-Day, Reuters photographer Chris Helgren compiled archive pictures taken during the 1944 invasion, and then visited the same places to photograph them as they appear today.