Catedral Basílica de la Inmaculada Concepción

Spanish Wikipedia says works were ordered by Bishop Pedro Loza y Pardave and began in 1855 or 1856, with sources differing. Father Miguel Lacarra resumed and accelerated the building in 1875, and Estanislao Leon designed and built the church and died during the final stages. The first public mass is recorded on 7 May 1880, the towers were begun in 1893 and the first was finished on 6 April 1894, with the second a few months later. The temple and its altars were blessed and consecrated on 7 May 1899, and English Wikipedia describes the construction as running from 1856 to 1899. Wealthy benefactors helped pay for the work, among them Pedro Echeguren y de la Quintana.

The church has a basilica plan with three naves of equal height. An octagonal dome with a lantern, crowned by an iron cross, rises over the crossing, and the two towers have two levels each, ending in truncated prismatic caps topped with crosses. Spanish Wikipedia says the dome and towers are covered in yellow tiles of European manufacture. The facade has a porch with three ogival arches and a neo-Gothic portal under a triangular pediment, and sculptures of the four evangelists stand on the porch and side walls. An enclosed atrium holds monuments including two of Christ the King.

The interior blends Gothic, Baroque and Neoclassical elements with Neo-Moorish influence. The Gothic main altar has marble statues of saints and angels from Carrara, and behind it a marble dome frames a sculpture of the Immaculate Conception and a mural of the Holy Trinity. Four neoclassical side altars are dedicated to Our Lady of the Rosary, the Sacred Heart, Saint Joseph and Our Lady of Guadalupe. Frescoes were completed in 1942, and French cut-crystal chandeliers were installed in 1950. The article also records an organ built in Paris by Aristide Cavaille-Coll, first played, according to newspapers, on 17 May 1899.

The church was dedicated to the Immaculate Conception on 8 November 1938 according to English Wikipedia, and declared a minor basilica on 12 December 1941 by Pope Pius XII. It became a cathedral in 1958, when Pope John XXIII created the Diocese of Mazatlan, and the first bishop, Miguel Garcia Franco, is buried in the Guadalupe altar. It is a listed historic monument and part of Mazatlan's Centro Historico, designated in 2001. A private guided walk can link the cathedral with the historic center around it.