Fifteen years after the horrific attacks, the pain of 9/11 is as fresh as ever in New York, Washington and across the United States.   But sadly, extremist brutality did not stop that day.  From San Bernadino to Yemen, Paris to Bangladesh the reach of a sophisticated and persistent enemy has only grown. The effects of Al Qaeda, ISIS, the Muslim Brotherhood, Iran and their proxies reach far into Europe, America and Asia. But in the Middle East, in the heart of the Arab world, we face an existential threat from extremism. Our communities, our families, our livelihoods, our entire way of life are exposed and under constant attack. Read the UAE ambassador's input on 9/11.