This book analyzes the places of worship used during the eighteen feasts of the Nahua solar calendar, called veintenas, and the ceremonial paths of the participants in the ceremonies in the Aztec capital of Mexico-Tenochtitlan. The work is based on thestudy of written sources of the sixteenth century, the pictographic manuscripts of pre-Hispanic times and their copies of the first colonial era, as well as archaeological data. In this way a comprehensive overview of the buildings and open spaces used during the monthly rites is presented. Each chapter is devoted to the study of a month and its ceremonies and is divided in two parts. As the first part describes the sacred spaces, the second one examines the ceremonial paths, its participants and the moments of realization. This investigation is enriched by the study of their localization in the sacred geography of the city. The conclusions obtained help to understand some of the new aspects of Aztec religious life: the symbolic significance of places of worship, the geographical distribution of the centers of supernatural power in the urban space and their usage. In this way, these data reflect the worldview of the ancient Nahuas.