‘From the second half of the twentieth century, architecture became aware that the ground was also a territory for design. In the fifties, Pikionis’s delicate design for the Acropolis access in Athens taught architects to look down again, just like some premodern cultures had done when designing tiles and pavements.’ This essay written for Electra by Chilean architect, researcher and curator Francisco Díaz tells us about this return. His latest book, published this year, is actually entitled Suelos [Soils]. Taking the City of Culture in Santiago de Compostela as a case in point, he tells us about the relationship between soil and terrain. Grounded in various types of knowledge, Díaz's gaze at the same time questions, investigates, guesses, discovers, records and ponders.