Special lighting efects, popularly known as “the miracles of light”, take place at the solstices or equinoxes in three medieval churches located in the Spanish city of Burgos and its surroundings. These hierophanies can be observed in religious buildings whose design and construction were carried out by medieval architects associated with what is known as “taller de los Colonia”. The underlying assumption of the research is that the same efects were also generated in the Conception Chapel of Burgos Cathedral and were visible until the Chapel of Santa Tecla was built in the 18th century. This paper virtually reproduces these lighting efects using solar simulation software tools and analyses the methods used to generate them.