Visible crew/equipment: Anita Ekberg's character and Marcello are at the top of the church tower leaning on balcony railing while looking over the city. You can easily see the "wire" attached to Anita's hat that forecasts the moment where her hat blows off her head. (00:33:15)
Continuity mistake: When Marchello is on a rooftop restaurant before opening time he is trying to type something as a journalist but he keeps getting distracted, so he asks the girl who works there to turn the jukebox off, which she does by pulling something from behind it, like the power cord. When he asks to have it turned back on, the girl just presses something simple in the front, instead of at the back, which she should have done.