The Tunguska event is the largest cosmic calamity caused by the impact of an interplanetary body with the Earth atmosphere that happened during historical times. A two-week scientific expedition (Tunguska99, http://www-th.bo.infn.it/tunguska/) to the impact site has been carried out starting from 14 July 1999 by the Department of Physics of the University of Bologna, in collaboration with researchers of the Turin Astronomical Observatory and of the Institute of Marine Geology (CNR Bologna). A camp was built in the taiga, at some hundred kilometers from the nearest roads. Personnel and researchers, mainly from Tomsk (Russia), provided local support. .....
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