A cracked sand bed, some dry bushes struggling against the heat, and no trace of saltwater on the horizon—this almost surreal scene awaits the few visitors who make their way to the theoretical mouth of the Colorado River in the Sonoran Desert. For over 25 years, this mighty 2,300-kilometer (1,400-mile) river has literally evaporated before reaching its destination. The phenomenon is not due to climate change or an exceptional drought. Instead, it is the result of human activity and infrastructure. Since 1998, the Colorado River has no longer naturally reached the Gulf of California, having dried up before its mouth. The Hoover Dam and water-sharing agreements dating back to 1922, based on an overestimated flow, have led to a legal over-allocation of the river’s water. About 80 percent of the diverted water is used for agricultural irrigation, depriving the Mexican delta of its fresh water and transforming it into a salt desert. The Colorado River originates in the majestic Rocky Mountains in the heart of Colorado and begins a long journey through seven U.S. states and then Mexico. Along its course, it shapes some of the most spectacular landscapes on the planet, including the famous Grand Canyon, before theoretically heading toward the Gulf of California, also known as the Sea of Cortez. Theoretically, because since 1998, not a single drop of this river naturally reaches the ocean. This paradox is surprising: how can such a powerful river, capable of carving canyons millions of years old, simply disappear into the sand before reaching the sea? The answer lies not in the sky, but in how human societies have decided, for nearly a century, to share this resource that has become precious. The Hoover Dam, the wall that changed the fate of an entire river, is central to this story. Built in the 1930s at the border between Nevada and Arizona, this monumental structure marked a definitive turning point in the river’s destiny. By retaining billions of cubic meters of water in Lake Mead, the largest artificial reservoir in the United States, humans have transformed a free and wild river into an immense reservoir managed, controlled, and redistributed according to the needs of cities and agricultural operations. This engineering feat, celebrated at the time as a technological miracle, now supplies water to rapidly growing metropolitan areas such as Las Vegas, Phoenix, and Los Angeles. The problem is that the agreements signed to share this bounty date back to 1922, a time when the river’s flow was exceptionally high. Today, however, more water is legally allocated than the river actually transports. This imbalance largely explains why the Colorado River runs dry long before its natural mouth. The denouement of this story takes place in Mexico, in what was once one of the richest ecosystems in North America: the Colorado River delta. This vast wetland, once teeming with biodiversity between fish, migratory birds, and mangroves, has gradually transformed into a sterile salt desert, deprived of the fresh water that once made it rich. In response, binational agreements between the United States and Mexico, known as Minute 319 and Minute 323, have sometimes allowed for the organization of occasional water releases, nicknamed pulse floods, to temporarily give back a bit of life to this dying delta. These initiatives, although symbolically strong, remain increasingly difficult to maintain as the pressure on the region’s water resources continues to intensify. Thus, the Colorado River is not the victim of a simple climatic whim: it is above all the symbol of a human management system that has become untenable. Between oversized dams, insatiable irrigation canals, and increasingly thirsty cities, this mythical river tells, better than any speech, the limits of our relationship with natural resources. As other great rivers around the world face similar tensions, the example of the Colorado River invites us to seriously reconsider our way of sharing water before other rivers suffer the same tragic fate.