Of all the sitcom families who defined the 1970s, there's none we'd want to knock on the door of more than Jack, Janet, and Chrissy. Since first hitting the small screen in 1977, Three's Company enthralled audiences and kept them laughing for so long that their salads got cold. 

From sweet stills to fun nights on the town, here are 21 iconic photos from the glory days of Three's Company.