The British Prime Minister is calling for world leaders to set their differences aside as they gather in Normandy to mark 70 years since D-Day.
David Cameron is joining the Queen, Russia's President Putin, France's Francois Hollande and the US President Barack Obama for a service on one of the beaches where allied troops landed.
The hour-long ceremony features a re-enactment of the moment troops came ashore, and is being attended by 17 heads of state, as well as 1,000 D-Day veterans.
Ukraine's president elect and the Russian President have met on the sidelines.
Petro Poroshenko and Vladimir Putin apparently spoke for 15-minutes - about the Ukrainian elections, and a possible ceasefire.
Mr Putin also spoke briefly to the US president Barack Obama.
By the end of D-Day on 6 June 1944, the Allies had established a foothold in France - an event that would eventually help bring the war to an end.
Sir Winston Churchill's granddaughter, Celia Sandys (pron: sand-ez) says fatalities were her grandfather's biggest concern on this day in 1944:
