The place is outside center, but it is easy reachable by underground (1,5 EUR one way). The basilica has the same beauty and greatness as Basilica di San Pietro in Vatican and it is very little people who is visiting this place. So you could spend whole hours to look around, see sculptures and frescas and not be disturbed by other tourists. Place is amazing also for pilgrimage, because Basilica is made over remains of Saint Paul. Specially worth to take walk in beautiful garden of basilica.