(NBC) - The games start in just four days and the scene is being set for Friday's opening ceremony.
Athletes are still arriving as final preparations are underway security is tight and highly visible.
As officials work to keep everyone safe from potential threats.
You couldn't really get any more obvious, when it comes to Rio trying to make you feel safe.
On Copacabana, and almost everywhere you look here near the venue for the opening ceremony, there's someone smiling, with a gun.
But they seem to have missed something, quite important.
"Well, it's one of the biggest challenges for organizers here, security screening for the huge crowds who want to get into the venues, but the vital task of who's going to be manning the x-ray machines at the end of these lines down to the very last minute.
Just one month ago, they hired a contractor to man these machines.
On Friday Brazil's justice minister announced the national guard would take over, as the contractor wasn't ready.
But still, some employees of the contractor say they were still being asked to come to work this weekend.
One agreed to talk to us, anonymously for fear of reprisals.
He said he says he wasn't asked to provide a police criminal background check and only had to do a quick online training course.
"There are people who turn up for the job without any real training for the kind of work we're being asked to do. Our job is to look after people's security, and some of the people doing the work, in my view, aren't up to that. The training course was very quick. I think there should have been more to it", said one employee.
It's not clear whether he's needed again, or - he says - when he'll get fully paid.
"Today I was meant to do a six-hour shift, but did eight hours. At the end, the supervisor came and said they said they didn't know when we had to come back to work again. I've done three days and others have worked for more than a week, and none of us have received the travel or food expenses yet", said the employee.
The IOC chief Thomas Bach says he has total confidence in the security of the games.
The government says they're drafting in thousands of retired police and firefighters to help.
On Copacabana, security is almost too much.
But away from the bright lights, with three days to go, some are asking, what else has been missed?