Tunguska event - 12 megaton explosion in 1908 over East Siberia, flattened 80 million trees over an area of 2,150 km2 (830 sq mi). Generally attributed to a meteor air burst, no impact crater found.
The explosion registered at seismic stations across Eurasia, and air waves from the blast were detected in Germany, Denmark, Croatia, and the United Kingdom – and as far away as Batavia, Dutch East Indies, and Washington, D.C.
Or what do you think, which part of the story is not true? The explosion happened that's sure, and the size should be at that range. In 1908 there were not much ways to make an explosion this big, we are well before nuclear bombs.