Photo taken on April 10, 2017 shows flowers placed at the tombstone of a victim of the plane crash in Smolensk of Russia, at the Warsaw Powazki Military Cemetery in Warsaw, capital of Poland. Poland marked on Monday the seventh anniversary of the plane crash in Smolensk of Russia in which 96 Polish people, including the then-Polish President Lech Kaczynski, were killed. (Xinhua/Chen Xu)
