Macron and Starmer lay wreath at Paris' Tomb of the Unknown Soldier on Armistice Day

With armed conflict once again on their continent, many European leaders marked the end of World War I, 106 years ago, with warnings that liberty — often taken for granted —must be cherished and defended.

British Prime Minister Keir Starmer and French President Emmanuel Macron, both leaders of nuclear-armed nations, attended a ceremony at Paris's iconic Arc de Triomphe, where wreaths lay under a milky light and the eternal flame flickered in honour of the unknown French soldiers who perished in the first global conflict. That war killed almost 10 million soldiers.