Polish President Andrzej Duda (L) attends a ceremony at the Lech Kaczynski Monument in Warsaw, Poland, on April 10, 2019. Poland's political leaders are leading throughout Wednesday a series of commemorative events to mark the ninth anniversary of the Smolensk plane crash, which killed 96 people, including former Polish President Lech Kaczynski. (Xinhua/Jaap Arriens)