The 2003 US-led invasion of Iraq, dubbed "Operation Iraqi Freedom," began 20 years ago. The Bush Administration told the world that Saddam Hussein was developing weapons of mass destruction and the war would last weeks, but none of that was true.

In fact, almost nothing in the Iraq War went as planned. The US wasn't prepared for a violent insurgency that lasted years, killing thousands of US troops and hundreds of thousands of civilians. And two decades from its start, the war still casts a long shadow––the rise of ISIS, a civil war, ongoing violence and political turmoil.