Every year on 11 September, bells ring to commemorate the exact time that each of the four planes crashed, and the exact time that the Twin Towers fell, followed by a moment of silence. This year, a seventh bell rang. Its purpose was to commemorate the thousands who died from diseases including cancer after the attacks. Illnesses related to dust and smoke from the towers' collapse have since claimed more than threefold the nearly 3,000 lives lost in the attacks, US health officials say. Tap the link in BBCNews’s bio for more on the tributes taking place globally to mark the 25th anniversary of the 9/11 attacks. (📷 Getty) #911 #TwinTowers #BBCNews