Martedi in Arte — that fantastic tradition where, on the last Tuesday of each month, major state museums in Italy are open and free from 7pm-11pm — is a hit. Such a hit, it's going on all year long.

Here in Rome, participating sites include the Palazzo Massimo (a savings of €10!), a treasure trove of ancient art and sculpture; the often-overlooked, but useful, Crypta Balbi; the Pantheon (always free, but only open so late for occasions like this one); the Palazzo Barberini, filled with gems by Raphael, Caravaggio and more; Castel Sant'Angelo, the papal castle; and the Galleria Borghese, that world-renowned collection of pieces by everyone from Bernini, Raphael, and others.

So mark your calendar: The next Martedi in Arte is May 31. But if you miss it, don't worry. You've got more shots… on June 28, July 26, August 30, September 27, October 25, November 29, and December 27. Phew!

Here's a list of museums across Italy participating in Martedi in Arte.