Spoletosfera is a technical structure called "geodesic", donated to the city of Spoleto in 1967 by the author/inventor architect Richard Buckminster Fuller on the occasion of the 10th Festival dei Due Mondi. The geodesic dome, patented by Fuller in 1954, reproduces the flattened sphericity of the earth (geoid). It is something halfway between a work of art and a technical structure: it is made up of a combination of prefabricated triangular metal elements, connected by nodal joints, arranged in such a way as to allow it to support itself, without the need for internal walls or supporting pillars. Covered with a canvas, it becomes an environment that can be used for off-site performances, conferences, recitals and art exhibitions. Over time it has hosted artistic events of various interests: happenings, installations, performances and concerts.