The small museum, hosted on several levels, contains artifacts, photographs, paintings, and other vintage items that tell the stories of faith related to the Metropolitan Cathedral and the veneration of Our Lady of Peñafrancia. Visitors can also visit the roof deck where the ten-foot tall image of the Inang Penafrancia, flanked by two angels, is installed. The view of the Cathedral Grounds and surrounding areas seen from the top portion of the arch is impressive, especially at night.

The Porta Mariae Museum is open this Fiesta Season, with guided tours from 9:00 am to 9:00 pm. Admission fee is P30.