Organized by the Guggenheim Museum Bilbao in collaboration with the Fondation Beyeler, this exhibition explores the meaning of the concepts of time and space in the oeuvres of Constantin Brancusi and Richard Serra, two of the finest sculptors of the 20th century. Some 30 sculptures by Brancusi, shown in themed groups to point up aspects of his artistic output, are to be placed against, and in dialogue with, thirty or so works by Richard Serra. In both cases, the exhibition stresses the effects produced by the variety of materials used, Brancusi availing himself at different times of marble, wood, cement, plaster, and bronze, while Serra has leant more towards steel, rubber, lead, and even neon tubes. The occasional juxtaposition of works by the two artists leaves room for individual areas devoted to works by each one, thus pointing up their similarities and differences, while also revealing the dynamic spatial power of the sculpture itself. The architecture of the two exhibition venues plays a major role, by bringing a third voice to the selection of sculptures on display.