With beautifully carved porticos and interiors dripping with gold leaf, Potosí’s churches are amongst the finest examples of the mestizo-Baroque style, in which Christian European and pre-Christian Andean symbolism are combined. The churches were built partly as a straightforward expression of religious faith, but gratitude for the wealth of Potosí also played a role: whereas Catholic churches almost always face west, those of Potosí look south towards Cerro Rico. They were also part of a determined effort to convert the indigenous population: with hundreds of thousands of indigenous people from different ethnic groups spending time in the city as workers under the mita system, Potosí offered a perfect opportunity for inculcating the Catholic faith. As well as the many churches and convents built for their own use, the Spaniards built fourteen parish churches for exclusive use by the indigenous mitayos.