For Christmas 2007, GAMeC and Bergamo's Department of Culture invited six artists to reinvent the concept of the Christmas tree, installing six large trees in key locations around the city. The participating artists were Vedovamazzei in Piazza Mercato delle Scarpe, Sislej Xhafa in Colle Aperto, Andrea Mastrovito in Piazzetta S. Spirito, Getulio Alviani in Piazza Vittorio Veneto, Stefano Arienti in Piazza Pontida, and Alberto Garutti in Piazzale Marconi.
Mastrovito covered a large fir tree with hundreds of red plastic butterflies that branched out from the tree into Piazzetta Santo Spirito.