Less than a month after 9/11, the US invaded Afghanistan, launching what President George W Bush called the “War on Terror” - a series of seemingly endless wars and military campaigns spanning Afghanistan, Iraq and countries across the Middle East, South Asia and Africa.According to the Cost of War project at Brown University’s Watson Institute for International and Public Affairs estimates that US-led wars since 2001 have directly or indirectly killed an estimated 4.5 to 4.7 million people - including approximately 940,000 direct deaths and 3.6 to 3.8 million indirect deaths from disease, malnutrition and health complications.Afghanistan: 176,000 direct war deathsOn October 7, 2001, the US launched Operation Enduring Freedom. The Taliban fell within weeks, but the war went on to span nearly 20 years across four US presidents - the longest conflict in US history.An estimated 176,000 people died as a direct result of the war, according to an analysis from the Costs of War project, while hunger, disease and untreated injuries killed hundreds of thousands more.Food insecurity rose from 62 percent of Afghans before the war to 92 percent after it, and unexploded ordnance and landmines continue to kill and maim civilians.In 2021, the Taliban regained control of Afghanistan.In this January 28, 2012 photo, US soldiers, part of the NATO- led International Security Assistance Force (ISAF), patrol west of Kabul, Afghanistan [File: Hoshang Hashimi/AP Photo]Iraq: 315,000 direct war deathsLess than two years later, on March 19, 2003, the US launched its invasion of Iraq.Omar was 18 years old when the Iraq war began. “We remember the sounds [of the bombs]; we were very afraid,” he told Al Jazeera.Omar recalls how some of his friends went to see what was happening as the war reached Baghdad, despite warnings that it was too dangerous. “I told them, why are you going?” he says. “Then they went, and they didn’t come back. It’s very sad when we remember.”An Iraqi girl holds her sister as she waits for her mother to bring over food she is buying, in Basra on March 29, 2003 [Jerry Lampen/Reuters]