A city in Southern Spain holds an ancient secret to fighting extreme heat

A few meters below the former site of Seville’s 1992 World Expo, a promising climate experiment blending ancient technology and modern science is underway. Rows of black pipes run along the ceiling and down the bare concrete walls. These, in turn, connect to bright blue and green tubes and enormous silver pumps. In a control room to the side, an array of monitors display the heat, humidity and wind speed above. “We have deployed several types of cooling systems here, each one used depending on climatic conditions,” says Maria de la Paz Montero Gutiérrez, a researcher at the University of Seville, from down in the building’s bowels where she is helping supervise the project. In 2020, authorities began to install these cooling systems in two public spaces in the Isla de La Cartuja neighborhood of what is one of Europe’s hottest cities. Every day about 30,000 people come to work and study in this northwestern district, which is mostly non-residential and home to university campu