When you walk into a 7-Eleven at 2 a.m. and grab some munchies, you'll often start wondering why the convenience store is named after after two arbitrary numbers.

While we're used to the store being open 24 hours a day, seven days a week, there was a time when the store was only open, as you might guess, from 7 a.m. to 11 p.m.

A quick look at the 7-Eleven history shows the store's been around since 1946, when the Tote'm store changed its name in honor of its operating hours.

It wasn't until 1963 that the store started keeping its doors forever open, kind of by accident.

It started at a 7-Eleven location near the University of Texas that got so busy after a football game, the store was forced to stay open past its 11 p.m. closing time. After seeing how well their sales did that night, the Texas store decided to keep itself open 24/7, permanently.

Other 7-Eleven stores soon followed suit, and the rest is history.

Now, when you look up at the familiar lit up green and red sign, you'll know that its name actually came from its former operating hours.