The largest city in North America, Mexico City, sits at the center of a high valley, 7,000 feet in the air, surrounded by volcanoes. Over a millennium and a half ago, a volcano called Xitle erupted. Molten lava poured into the valley and covered around 30 square miles in a bed of volcanic rock. Today, most of this lava field has been paved over with roads and buildings and parking lots, but there is still one area where the volcanic rock can be observed on the surface.

The Pedregal de San Angel Ecological Reserve is a small park in South Mexico City where visitors can observe swirls and folds in rocky outcroppings, remnants of the lava that flowed and cooled centuries ago. When the area is hot and dry, brown grasses creep up through the cracks, but when the seasonal rains come, the landscape transforms, bursting with color as various plants begin to bloom.

Back in the 1940s, this unusual landscape became a source of inspiration for Mexican Modernist architect Luis Barragán. Famous for his bold uses of color and careful integration of natural light, he designed a number of homes among the rocks of El Pedregal. In attempting to build harmoniously with this volcanic landscape, however, Barragán may have accidentally contributed to an ecological crisis that’s playing out in Mexico City today.

Paving Paradise

Luis Barragán moved to Mexico City from Guadalajara in the late 1930s. The city was in the middle of a building boom, but around 10 miles south of the city center, El Pedregal remained relatively undeveloped. Barragán and his artist friends would go on weekend hikes in the lava field. In part, they were enamored with this landscape that felt distinctly Mexican. “It was a place that the Spanish had never tamed … had never colonized,” explains Keith Eggener, an architectural historian at the University of Oregon. “It was a place with views of the volcanoes that were central to a lot of Mexican mythology and Mexican history.”

For years the uneven rocky landscape deterred would-be developers, but Barragán saw the lava as an asset. He decided to populate the place with modern houses while leaving much of the lava and natural vegetation in place. Like Frank Lloyd Wright did with Fallingwater, Barragan would integrate the landscape into his designs. The homes themselves would be simple and modern, made of local materials and deferring to their context. In some places, the lava rock would even intrude into the buildings. The streets would follow the contours of the rocks as well. Much of the land would be left open and unbuilt.

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Keith Eggener has been a member of AAH since 1987, and is the current editor of JSAH.