Newsround viewer Molly has travelled to Normandy in France with her granddad to remember D-Day.
70 years ago today, British, Canadian and US troops stormed the beaches of France.
It's a key date in the story of World War 2 and happened on 6 June 1944 after five years of war with Germany.
Molly's granddad was a Royal Engineer in the war and has shared his memories of D-Day with her.
We spoke to Molly on the telephone and she told us why remembering D-Day is important to her.