Built in the 14th century as the entrance gate and tower in the wall that surrounded the city. Reconstructed in the 16th century by Juan de Vallejo and Francisco de Colonia as a triumphal arch. It presents the Emperor Carlos V surrounded by the most significant characters in the history of the city and of Castile. The Sala de Poridad stands out, meeting place of the Council of Burgos until the 18th century with civic motifs and Mudéjar coffered ceilings. In the Main Hall painting by Vela Zanetti, remains of Mudéjar plasterwork and the pharmacy of the old San Juan Hospital.