"Since 2000, Serpentine has commissioned internationally renowned and emerging architects to create their first built structure in England. The aim of our Pavilion commission is to choose architects who consistently extend the boundaries of contemporary architectural practice and to introduce these practitioners to wider audiences. We invite the architects to design a Pavilion that is used as a meeting space and café by day and a forum for learning, debate and entertainment at night. The Serpentine Pavilion series was the first scheme of its kind worldwide at this level of ambition and presents commissions that push the boundaries of contemporary architectural practice."
Video and summary via https://www.serpentinegalleries.org/about/serpentine-pavilion.