Thousands of people around the world commemorated on Sunday the centenary of the armistice that ended World War I, the so-called Great War that left millions dead and reshaped European borders, international warfare and society.

In Paris, President Emmanuel Macron of France, Chancellor Angela Merkel of Germany, President Trump and President Vladimir V. Putin of Russia were among the dozens of world leaders who gathered to observe the moment when guns fell silent after four years of brutal warfare.

In London, members of the British royal family, Prime Minister Theresa May and Jeremy Corbyn, the opposition leader, laid flowers for the war dead, and thousands of veterans and ordinary citizens marched in tribute to those who had sacrificed their lives.

Pope Francis addressed crowds at the Vatican, and memorial services were held in Australia, Belgium, India, Ireland and New Zealand, among other places.