This dispute has been going on for many years. The picture of that day in 1908 will forever remain in the memory of eyewitnesses. The banks of the Upper Tunguska are wild, rocky, gloomy. Immediately behind them is the centuries-old taiga. And suddenly a terrible blow. Behind him comes a second blow, more terrible. The air is thick, heavy and knocks you off your feet. What was it? An atomic explosion, the fall of a comet, a huge meteorite, the death of a spaceship? This debate about the explosion has been going on for many years.