A capilla abierta or “open chapel” is considered to be one of the most distinct Mexican construction forms. Mostly built in the 16th century during the early colonial period, the construction was basically an apse or open presbytery, containing an altar, which opened onto a large atrium or plaza. While some state that these were constructed by friars because the native peoples of that epoch were afraid to enter the dark confines of European-style churches, the more likely reasons for their construction were that they allowed the holding of Mass for enormous numbers of people and the arrangement held similarities to the “teocallis” or sacred precincts of pre-Hispanic temples. While open chapels can be found in other places in Spain and Peru, their systematic use in monasteries and other religious complexes, leading to a regularization of architectural elements, is only found in Mexico.