The Atzacoalco Route leads you into the old northeastern barrio of ancient Tenochtitlan. This corner of the island capital, San Sebastian Atzacoalco, and Santiago Aztacoalco across the water, marked the northern and southern ends of one section of dike built by Nezahualcoyotl in 1449. This was a major hydrological work that kept Tenochtitlan surrounded by fresh water for nearly 60 years until the Spanish invasion.
Walking north from the Zocalo, one encounters some of the oldest parts of the city. The Atzacoalco Route can easily be supplemented by those that cover the Calle Donceles, and the Plaza de Santo Domingo area. All of them include a wealth of insight for the determined traveler.