President Donald Trump gathered with other world leaders on Thursday to commemorate the 75th anniversary of D-Day, in which allied troops invaded Normandy to move against Nazi control of France.

With hundreds of thousands of troops across an array of allegiances dying that day, the world leaders signed a solemn proclamation to mark it. The proclamation notes the horrors each country faced in the wake of World War II, and the leaders acknowledged their responsibility in making sure conflict of that degree never happens again.