Free museum hours in Rome change with the day of the week. This is the list for Wednesday: first what is free on this day in particular, then what is free on any day.
Free walking tours in Rome1
These have no fixed price. You reserve a spot, and at the end you tip the guide what you think the tour was worth.
San Luigi dei Francesi (Caravaggio)Piazza NavonaAlways · Monday to Friday 9:30–12:45 and 14:30–18:15, Saturday 9:30–12:00 and 14:30–18:30, Sunday 12:00–12:45 and 14:30–18:30. Closed the morning of the first Wednesday of the month.
Appian Way (Via Appia Antica)Appia AnticaAlways · open at all hours. Car-free on Sundays and holidays 9:00–18:00 in summer time, 9:00–16:00 in winter time. Past the tomb of Cecilia Metella, traffic is restricted every day.
Non-Catholic CemeteryTestaccioMonday to Saturday 9:00–17:00 (last entry 16:30), Sundays and holidays 9:00–13:00 (last entry 12:30). No fixed fee. A donation of at least €5 is requested.
Papal General AudienceVaticanWednesdays at 10:00 when the Pope is in Rome. Gates open about two hours earlier. Check the calendar, some weeks are cancelled.
Trevi Fountain (from the piazza)TreviAlways from the piazza · 24h. The paid basin area runs 9:00–22:00 (from 11:30 on Mondays and Fridays), last entry 21:00.
Bernini's Apollo and Daphne and the Rape of Proserpina are here, plus six Caravaggios, and no church or free Sunday elsewhere comes close for sculpture. Entry is by two-hour timed slot with capped numbers, so you can stand in front of the marble without a crowd. Book a week or more ahead.
Everything above is free. This is the only paid pick on the page, chosen because no free option replaces it.