"Alive" explores a new vision of probiotic buildings. It is a prototype for architecture that promotes human health by promoting diverse microbial communities through the calibration of light and air flow. It involves a room made of porous, organic material with both macro-spaces for humans and micro-spaces for microbes - and interfaces for exchanges among different species. In a broader sense, this project is a model for a new spatial contract. To live together in the future, humans will thrive by sharing space with other humans and with many types of microbes.