It was a pivotal day in world history as the United States, and several allies, invaded Iraq under the suspicion that then-President Saddam Hussein was amassing weapons of mass destruction.
The March 20, 2003, invasion led to an eight-year conflict with over 4,400 American troops killed, and nearly 32,000 wounded during the conflict, according to the Department of Defense. Reports by groups, such as the nonprofit online database the Iraq Body Count, said that nearly 200,000 Iraqi civilians were killed during those years.
No weapons of mass destruction were ever found and Hussein was apprehended, tried and executed.
"Nightline" took a look back at the 20th anniversary of the conflict with some Iraq War veterans who were profiled on the show just before they were deployed.
Even though it's been two decades since they were among one of the first troops sent overseas, Retired Marine Corporal Michael Elliot and Retired Marine Corporal Josh Hisle told "Nightline" have only recently healed from the mental and emotional traumas of war.
"The war took a big toll on my life," Elliot, 41, told "Nightline." "The military and war threw me into the deep end."
Elliot and Hisle were among the 206 Marines of Fox 2/5 company out of Camp Pendleton, California.
"Nightline" embedded with the Marines before the invasion, filming as they waited for official orders. Hisle, now 41, played guitar for his troops when they were getting ready in Kuwait.
"I still just remember it being this one evening for a minute where it was such a good time that you almost forgot," he told "Nightline" co-anchor Byron Pitts.
The troop would see combat not too long after it deployed and suffer a major loss. On April 4, 1st Sgt. Ed Smith, who postponed retirement to serve in Iraq, was killed when a piece of shrapnel struck his head while their convoy was trapped next to an ammunition dump fire.
"We're all standing up exposed, and he made the call to have everybody get back in the vehicles," Elliot said.
Smith's daughter, Shelby Robinson, who was 8 when her father was killed, told "Nightline" that Smith was always proud of his military experience. She's now a police officer and said her father inspired her.
"That makes me feel very close to him. And I definitely think that he's watching over me out there," Robinson told "Nightline."
Marine Col. Terry Johnson was Fox 2/5's commander when the war began. He told "Nightline" that war had its consequences and many of his brave comrades paid the ultimate price for their service.
Johnson, now 52, who is set to retire this year, said he believed the U.S. involvement in Iraq was worth the price that was paid.
"Clearly Saddam was a bad individual, was a dictator of classic proportions, was extremely brutal to his people," he told Pitts.
Not all of his colleagues believed the war was completely warranted.
Elliot and Hisle both said they had trouble adjusting to civilian life after they were honorably discharged and left the Marines feeling remorse for some of the actions and directives they were given in Iraq.
"Every mission, everything we did, kicking doors and disrupting people's lives, bagging people's heads, bagging the dude's head and dragging him out of the house, while his kids are standing there screaming, for what? What are we doing?" Hisle said.
Hisle said he feels that America didn't learn anything from the war because civilians' lives weren't affected.
Elliot said he felt heartbroken because the post-military life for newer veterans is getting more difficult and nothing is being done to help.
While they were diagnosed with PTSD and sought help, they said the road to recovery was challenging in ways they couldn’t have predicted.
"Everything I did in combat is not going to work in civilian life. Now I have to re-learn again. And how do I take care of myself? I'm going to drink, I'm going to numb myself. I'm going to drink until I pass out," Elliot said.
After the war, at least three Fox 2/5 Marines died by suicide, and one of them is in prison for murder after allegedly suffering from PTSD.
These Marines are a snapshot of an alarming reality for America’s vets.
In 2019, 17 veterans died by suicide every single day and 29.3% of veterans who fought in Iraq and Afghanistan have been diagnosed with lifetime PTSD, according to the U.S. Centers for Disease Control and Prevention. Nearly 13% of homeless adults are veterans, according to the National Coalition for Homeless Veterans.
Both Elliot and Hisle said they are doing better. They both graduated college after their service. Elliot is now working as a physical therapist and Hisle is working in a local government job.
"Even with support and all the encouragement from my friends, it's only been a couple of years...where I've experienced this inner peace," Elliot said.
"It's a hard journey and you have to decide if it's worth it," he said.
Free support to those facing a suicidal crisis is available by calling the National Suicide Prevention Lifeline: 988 or 1-800-273-TALK (8255)