Rome, Italy - December 30, 2018: Basilica di Santa Maria Maggiore in Rome, Italy. Santa Maria Maggiore, is a Papal major basilica and the largest Catholic Marian church in Rome, Italy.. Rome, Italy -December 30, 2018: Basilica di Santa Maria Maggiore in Rome, Italy. Santa Maria Maggiore, is a Papal major basilica and the largest Catholic Marian church in Rome, Italy.