This splendid example of Baroque architecture was designed according to plans by Fontana and modified by Martin de Zaldua. It was officially inaugurated in 1738. Note the Churrigueresque high altar, designed by Ignacio de Ibero. The richness of its stone marquetry is particularly impressive. A silver statue of St Ignacius has dominated its centre since 1758. This circular building is crowned by a huge 65m-high cupola built by Churriguera.