Most of Hilma af Klint’s deeply spiritual abstract paintings, which enjoyed a landmark 2018 exhibition at the Guggenheim Museum that cemented her as an unsung pioneer of abstraction—are held together at the Hilma af Klint Foundation. This exhibition reveals a newly discovered group of rare watercolors from the late Swedish artist’s Tree of Knowledge series made for Rudolf Steiner, who founded the spiritual and philosophical movement Anthroposophy. Each of the eight paintings feature variations on a tree with a heart-shaped crown—dynamic compositions that mix biblical references, esoteric iconography, and vivid colors that recall Art Nouveau stylings and speak to the circle of life and death.