Poland on Sunday marked the sixth anniversary of plane catastrophe in Smolensk, which took the life of 96 Polish people, including then-Poland's President Lech Kaczynski and his wife.   On Sunday morning, President Andrzej Duda took part in the commemorative mess in the Royal Wawel Cathedral in the city of Krakow, followed by placing flowers on the grave of former president Kaczynski and his wife.   Meanwhile, in Warsaw, at nine o'clock, in front of the Presidential Palace, Polish Prime Minister Beata Szydlo, Chairman of the ruling Law and Justice party, twin brother of the deceased president, Jaroslaw Kaczynski, accompanied by other major political figures and Warsaw citizens, took part in the Call of the Fallen.   Names of the victims were read aloud, and white and red flowers wreaths, symbolizing Polish flag, were placed before the picture of the couple.   Further commemorative events with representatives of government, Warsaw city authorities and victims' family members were held at the Warsaw Powazki Military Cemetery.   Both ceremonies were assisted with military salutes and honors for the deceased.   Xinhua reporters also witnessed many Warsaw citizens coming to put flowers, light candles, or express their grief and memory in other ways.   In the afternoon, commemorative plaques will be unveiled, while President Duda and Jaroslaw Kaczynski will give speeches. The events will wind up with Call of the Fallen held at nine p.m. in front of the Presidential Palace.   Apart from the commemoration within the territory of Poland, a delegation composed of victims' families and officials, headed by Anna Maria Anders, attend memorial services held in Smolensk and Katyn.   The Polish air force plane was heading to Russia to take part in events commemorating Polish victims of Katyn executions in 1940, but tragically crashed in the city of Smolensk on April 10, 2010. Apart from president Lech Kaczynski and his wife Maria Kaczynska, more than 90 high officials and plane staff died in the crash. Source:Xinhua