The retractable roof on top of the Falcons' new stadium has been one of the biggest construction headaches in the history of professional sports. 

Putting the roof together has been so complicated that the opening of Mercedez-Benz stadium has been delayed four times. First, it was supposed to open March 1, which then got pushed back to June 1, before being pushed back to July 30. 

Now, the stadium will be opening Aug. 26, which will be just in time for the Falcons' Week 3 preseason game against Arizona. 

The reason the roof has given the construction crews so much difficulty is because it's never been done before. When it opens, the one-of-a-kind retractable roof is supposed to look similar to a camera aperture opening.

If you're having some problems trying to imagine exactly what that looks like, don't worry, because there's now video, thanks to Mercedes-Benz's stadium's official Twitter account. 

Let's take a look at what the roof is going to look like once it's functional. 

Now, just because the roof is working in that video doesn't mean it's actually functioning yet. As the tweet notes, that's a time-lapse video, which means the roof actually took several hours to open because construction workers had to open it manually. 

Once the roof is mechanized, it should be able to open and close in less than eight minutes. Unfortunately for the Falcons though, the roof isn't mechanized yet and isn't expected to be for awhile. 

The Falcons have already announced that the roof will be closed through September, and possibly longer, which means the retractable roof is basically just going to be a roof for at least the next two months.