Washington D., September 12: Blue lights dotted the sky of New York city with beams shining from the facades and spires of its iconic buildings as the city paid tribute to those who lost their lives in the terror attack in 2001.

"NYC shines in blue on the 19th anniversary of 9/11. #TributeinLight's twin beams remind us of our loss and the blue lights shining from the facades and spires of buildings like @OneWTC and the @EmpireStateBldg remind us of our solidarity and strength together. #Honor911," The National September 11 Memorial & Museum said in a tweet. 19 Years of 9/11 Attacks: Key Facts About Attack on World Trade Center And Pentagon That Happened on September 11, 2001.

"As Tribute in Light radiates from the NYC skyline tonight, we remember all the innocent lives taken far too soon 19 years ago. In darkness, we shine brightest," it said in another tweet.

On September 11, 2001, the United States faced the deadliest terrorist attack in world history. In a span of just 102 minutes, both towers of New York's World Trade Centre collapsed after planes hijacked by al Qaeda operatives crashed into them, claiming the lives of at least 2,753 people.