The fifth presentation of the day was led by Diego de Santiago, who offered a fascinating perspective on the hydraulic systems developed during the reign of Nezahualcoyotl. His talk focused on explaining why these systems were exceptional and how their legacy can inform our current water management practices. Santiago began by contextualizing the hydraulic achievements of the Texcocans, explaining how they inherited and perfected techniques developed by earlier civilizations such as the Teotihuacans and the Olmecs. He highlighted how arid conditions in the Texcoco region drove the need for innovative water management solutions. The speaker detailed the impressive hydraulic engineering program carried out under the leadership of Nezahualcoyotl. He described a complex system that included agricultural terraces, causeways, dykes, and aqueducts, all designed to maximize the use of available water resources. Santiago emphasized the sophistication of these works, noting that they represented an unprecedented achievement in pre-Hispanic Mexico. One particularly interesting aspect of the presentation was the description of the Albarradón, a 16-kilometer dyke that separated the saltwater of Lake Texcoco from the freshwater surrounding Tenochtitlan. Santiago explained how this structure not only protected against floods but also facilitated the expansion of chinampa agriculture in the region. The expert also addressed the multifunctionality of these hydraulic works. He explained how, in addition to their practical function, many of these constructions also served political, religious, and educational purposes. Santiago argued that this integration of functions is a key principle that we could apply in our modern approaches to urban planning and resource management. Santiago concluded his talk by reflecting on the lessons we can draw from this hydraulic legacy to tackle current sustainability challenges. He emphasized the need to rethink our relationship with water, seeking creative and comprehensive solutions for its sustainable management in the face of climate change. This presentation not only revealed the engineering genius of Nezahualcoyotl and his people but also demonstrated how solutions from the past can inspire and guide our responses to present environmental and resource challenges. Santiago's talk reinforced the central theme of the webinar: that ancestral knowledge can be a valuable source of inspiration for addressing the sustainability issues we face today.