From Madrid Planetarium: uprooted trees photographed by the 1991 expedition of the University of Bologna.

The Italian group explored the Tunguska site to search for microparticles from the cosmic body, trapped and preserved in the resin of surviving trees. This work made it possible to identify a first group of 14 elements as possible constituents of the cosmic body.The results obtained are published in Il Nuovo Saggiatore, Planetary and Space Science and Priroda. Some data about the biological effects of the explosion were presented at the Tunguska96 Conference.