For many centuries, even the popes made sure to make this a part of their 40-day prep for Easter.
The beauty of walking through Rome is that pretty much anywhere you walk in the city center, you are literally walking in the footsteps of ancient Romans and early Christians. Certain piazzas have served as gathering points since time immemorial.
One ancient Christian tradition, known as station liturgies, has been practiced as far back as the 5th century, if not even longer.
This tradition holds that during the 40 days of Lent, Catholics visit a different church each day for Mass. There is a schedule of which “station church” to visit on which day. Today, a Vatican academy makes sure that the Italian liturgies go smoothly at each church, while the Pontifical North American College (the US seminary in Rome) organizes liturgies in English at each of the station churches.
Monsignor Paolo Iacobone of the Pontifical Academy Cultorum Martyrum told the Vatican newspaper L’Osservatore Romano that originally the station liturgies took place at parishes and shrines that housed the relics of different martyrs, usually on that martyr’s feast day. The Christian community would gather and keep vigil, or pray for extended periods of time, while also fasting.
Eventually the station churches and days were expanded to include not only the feast days of certain saints and martyrs important to the early Christians, but other special days as well.