The PICO collaboration (PICASSO+COUPP) proposes the installation of a tonne scale dark matter search experiment at SNOLAB. The experiment is based on the superheated liquid technique, which due to powerful intrinsic background suppression features, promises background blind operation for up to tonne-year exposures. In this talk we will discuss the superheated liquid technique, the experimental program of the PICO collaboration and the physics reach of the project.