D-Day 72nd anniversary marked in the sand

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A Thank You is written in the sands of Omaha beach next to the Colleville American military cemetery, in Colleville sur Mer, western France, Sunday June 5, 2016, on the eve of the 72nd anniversary of the D-Day landing. (AP Photo/Francois Mori)

June 6, 2016 marks the 72nd anniversary of the D-Day landing in Normandy, France and the start of the European invasion by Allied troops during World War II.

Soldiers in France marked the occasion by writing messages of gratitude in the sands of Omaha beach next to the Colleville American military cemetery.

In 1944, Allied soldiers landed on the beaches of Normandy in what was a major offensive against the Nazi German forces.

Thousands were killed on both sides.