The United States on Sunday marked the 15th anniversary of the 9/11 attacks with solemn services all over the country. President Barack Obama will address a ceremony at the Pentagon, and the names of those who lost their lives will be read out in a remembrance service. The National September 11 Memorial and Museum in New York City will host its first art exhibition, called 'Rendering the Unthinkable: Artists Respond to 9/11'. It will showcase works by 13 artists who have been affected by the attacks.
More than 3,000 people died when two hijacked planes crashed into the World Trade Centre on this day 15 years ago. Terror group al-Qaeda orchestrated the attacks, which also involved two other hijacked aircraft that were targeted at the Pentagon and Washington DC.