The second chapel on the left was originally dedicated to St. John the Baprist. In 1861 the chapel was rededicated to San Giovanni Leonardi, who is enshrined in front of the altar. The chapel was designed by Giovanni Battista Contini in 1697, and commissioned by Cardinal Paluzzo Paluzzi Altieri degli Albertoni. The aedicule is spectacular, with a pair of massive red marble Corinthian columns and superb stucco detailing.