1the capital city of Italy, which is famous for its art, its history, and its many public and religious buildings from ancient times and the Renaissance. It also contains the Vatican City, a separate state where the Pope lives.
Rome wasn't built in a day
a phrase meaning that it takes time to achieve something important, and you should not expect to succeed immediately
When in Rome (do as the Romans do)
a phrase meaning that when you are in a different place you should behave like the people who live there
Definition from the Longman Dictionary of Contemporary English Advanced Learner's Dictionary.