A giant spider-like house made of recycled materials is just one of the many surprising projects that could emerge from the Bottom Up festival in Barcelona this weekend. Open to the public at no cost, this urban intervention project at eme3′s seventh International Architecture Festival will draw 50 participants from around the world. Artists, designers and architects will converge in different parts of the city to present a series of exciting design workshops that encourage uninhibited creativity – often using found materials. The Institute of Placemaking is among this year’s participants and they are planning to build fun new structures made entirely of recycled materials.