The Expiatory Chapel, commissioned by Vittorio Emanuele III in memory of the assassination of his father, Umberto I, on 29 July 1900, was designed by architect Giuseppe Sacconi, designer of the Vittoriano in Rome. The work was completed in 1910 so that it would be ready for the tenth anniversary of the attack. The memorial stands at the exact site of the tragedy and is surrounded by a tree-lined garden and a wrought-iron gate. The circular interior is covered with mosaics inspired by Byzantine culture and marble of various colours and many different origins. The side sails feature angelic figures with symbols of the Passion of Christ, while the roundels are decorated with figures of the saints and blesseds of the Royal Household. Underneath the chapel is a crypt in the shape of a Greek cross, decorated with polychrome marble and bronzes, whose vaults feature a starry mosaic sky. Furthermore, in the centre of the crypt, there is a black marble memorial stone engraved with the date of the attack, while ten windows are sealed with alabaster slabs. Benito Mussolini also visited the monument, carving the inscription "Monumento a Bresci" on a stone. Every year since it was first opened in 1911, a memorial ceremony has been held in the Expiatory Chapel on 29 July.