The urban structure of Castillazuelo is unique in the whole of Somontano: its streets are laid out in the shape of a cross, starting from the large central square in which the parish church is located.

This church is dedicated to Jesus the Saviour of the World. It is a brick building. On the outside, the two-part bell tower stands out.

Inside, it has a single nave covered by a barrel vault with lunettes, whose arches are decorated with simple plasterwork in the Mudejar tradition. Chapels were built between the buttresses: Santa Cristo, San Antonio Abad, La Purísima, San José, Virgen del Carmen and Virgen del Rosario. The entrance door is located at the foot of the church and has two semicircular archivolts.