Along the eastern side of the Basilica, a side door gives access to the majestic crypt that extends below the church along its entire surface. A vestibule leads to the burial ground of the Petrucci family, a room with brick columns and cross vaults, with the dominating funeral monument of Celia Petrucci (who died at fifteen years of age in 1558) consisting of a large travertine arch inserted in a . . .