The Anahuacalli is a unique piece of Mexican architectural heritage and, being the product of Diego Rivera with assistance from Juan O’Gorman, a legacy work of two of foremost figures in Mexican art history. Its site, composed mainly of harsh volcanic rock, is an ecological reserve. Its biodiversity is endemic to the southern end quarry of the Valley of Mexico, where much of the flora and fauna has been lost due to urban growth. Here, beautiful wildflowers spring from the volcanic rock, amidst a backdrop of prickly pears, tall grasses, and trees. The “Pedregal Pyramid” as Diego was fond of calling the museum, is the result of his deep background knowledge and lifelong obsession with pre-Hispanic cultures. The museum’s mission is to preserve and display the vast collection pre-Hispanic pieces Diego acquired during his lifetime—the Anahuacalli is considered a work of art in itself, an extension of the collection. For Riviera architecture should be a reflection of its society. The plaza, library, and remaining buildings were built after the museum, commemorating pre-Hispanic ceremonial gathering spaces. Diego conveys a message that pre-Hispanic architecture lives on within a museum: a temple of knowledge, the object of contemporary society’s devotion. The museum’s board of trustees invited four architecture studios to compete for a chance to build an expansion to the museum. Our entry did not win and will not be built, which is why we wanted to share it in this GA issue. Our proposal sought to preserve this fantastic space and open it up for its visitors to enjoy. Following this line of thinking we wanted to redefine visitors’ relationship with the ecological reservation by opening it up, moving away from its use as the museum’s ‘empty backlot’ as it sits now. The project focuses appreciating and enhancing the importance of the site’s cultural heritage by highlighting the existing community, local tradition, and regional culture in a design that makes effective use of the site. This way, the museum could become a gathering spot for the appreciation of the site’s natural, cultural, and artistic assets. When Diego Rivera acquired the land in Coyoacán, he thought it had high social potential. For Diego, who frequently referenced the “city of the arts,” the campus should exemplify a city in miniature. In Diego’s idea for the Anahuacalli, this mission is accomplished by the creation of independent workshops for arts and crafts, spaces for dance and music, and even an open-air auditorium capable of hosting parties and events for the community. This new city of the arts would bring a space for the Mexican people to confront and learn from their heritage, their arts, their crafts. Unfortunately, Diego died during construction and his dream was never fully executed. It was our intent to complete the creator’s idea of how the space should be used in addition to opening up its unique natural environment for people’s enjoyment. The program added onto the museum allows it to develop a social, cultural, and educative mission that attracts a varied public. Our proposal grows from the view first seen by visitors upon entering the museum. Along the main plaza a few volumes are added to house administrative functions. In a diagonal line on the opposite corner from the main entrance, adjacent to the “Pyramid” two perpendicular planes open up, suggesting a material palette different from the volcanic rock. Its slight copper reflection beckons visitors, inviting them to take a look. This space reveals itself to be a circular patio, lined with colored, curved glass that is the entrance to the administration. This area has a program of museum offices, the Diego Rivera archive, and as a threshold for visitors before they access the rest of the ecological reserve. From this point on, as the project develops into the site, topography becomes a key indicator and guide, having selected one level on which all buildings can be accessed. Program has been atomized along this level compelling visitors to explore the site. Each one of the workshops is accessible from this topographic level but responds to the site conditions such that some are perched above, some are ensconced in the rock, and others lie gently atop the ground. By atomizing the program into different volumes, it permits construction to be as minimally invasive as possible while allowing volumes to develop unique, independent personalities.Aesthetically, the new volumes of the museum’s expansion respect Diego Rivera’s own designs. The simple volumes, imagined as being built from compacted concrete, don’t look out of place in the plaza and out in the reserve arise as monolithic blocks, timeless and unflinching. Each block has one of its corners trimmed off revealing a circular patio vestibule lined with curved, copper-toned glass to mark the threshold at the edge and celebrate the city of the arts.