Cinecittà Studios (Italian for Cinema City Studios) is the main hub of Italian cinema and the largest film studio in Europe. It is closely associated with Federico Fellini and his works, but not only him. Many other great filmmakers have worked in Cinecittà, including Roberto Rossellini, Luchino Visconti, Sergio Leone, Bernardo Bertolucci, Francis Ford Coppola, Martin Scorsese, Mel Gibson, Wes Anderson, and George Clooney. Paolo Sorrentino's series The Young Pope and The New Pope were almost entirely shot at Cinecittà, including reconstruction of the interiors of the Sistine Chapel and Saint Peter's Basilica. BBC/HBO series Rome was filmed here and some of these sets were later used for an episode of the 2008 series of Doctor Who set in ancient Pompeii.

Overall, more than 3,000 movies have been filmed at Cinecittà, of which 90 received an Academy Award nomination and 47 of these won it.  

Federico Fellini first visited Cinecittà not as a film director but as a journalist. He was 20 years old, and he came to interview one of the actors. Several years later he started filming there and Stage 5 became his kingdom. He preferred the controllable universe of the studio to filming in an actual setting and he made most of his movies at Cinecittà.

Bonus fact: for his film  Roma Fellini built a whole highway at Cinecittà: half a kilometre long, four lanes wide, with billboards and rest stops. He could have used any of the highways in/around the city, but he liked working at the studio this much and he wanted everything to be perfect.

Bonus fact 2: right across Stage 5 and not far from Stage 10 one can find a gigantic head of Medusa from Fellini’s film Casanova.

Bonus fact 3: when the famous Swedish filmmaker Ingmar Bergman visited Cinecitta, the Studios’ director asked Fellini to show him around. They didn’t like each other much, and hardly talked during the tour. As Tony Griffiths described it in his book, ”Fellini was particularly distressed when Bergman <...> announced he wanted to have a pee. Fellini’s concern was that, coming from a country famous for excellent household appliances, Bergman would be shocked by what he saw in the Cinecittà’s staff toilets. He was.”

Sources: Wikipedia, https://cinecittastudios.it/en/, “Fellini” by Merlino Benito (Gallimard, 2007), “Stockholm: A Cultural History” by Tony Griffiths (Oxford University Press, 2009).