Rome Was Not Built in a Day

One time, after asking an employee when his assignment would be done, he told me that Rome wasn't built in a day.  I've read many history books, and none of them ever even suggested that Rome had built in a day, so I wasn't really sure what he was talking about.  I was even more confused because we weren't talking about building Rome - or any other ancient European city, for that matter.  In fact, we were talking about building real x-ray goggles that actually let you see through people's clothing, not like those cheap knock-offs you get at joke stores or at the airport.  Some people just don't know how to stay on topic.