The design of the church is based on the Pan­theon in Rome! What is inter­est­ing about the Rotun­da is that it was almost destroyed dur­ing World War II. On April 9, 1942, a Ger­man bomb pierced the dome of the church but nev­er explod­ed, while two oth­er bombs bounced off the dome and land­ed in the square with­out explod­ing either. This event became known as a mir­a­cle by Mal­tese peo­ple because more than 300 peo­ple were await­ing evening mass when it hap­pened. You can now find a repli­ca of the bomb inside that church, ded­i­cat­ed to this mirac­u­lous event.