An iron meteorite fell on the Sikhote-Alin Mountains, in southeastern Russia, in 1947. Large iron meteorite falls have been witnessed and fragments recovered but never before, in recorded history, a fall of this magnitude. An estimated 23 tonnes of fragments survived the fiery passage through the atmosphere and reached the Earth. Impact At around 10:30 AM on 12 February 1947, eyewitnesses in the Sikhote-Alin Mountains, Primorye, Soviet Union, observed a large bolide brighter than the sun that came out of the north and descended at an angle of about 41 degrees. The bright flash and the deafening sound of the fall were observed for around the point of impact not far from Luchegorsk and approximately northeast of Vladivostok. A smoke trail, estimated at long, remained in the sky for several hours. As the meteor, traveling at a speed of about , entered the atmosphere, it began to break apart, and the fragments fell together, some burying themselves deep. At an altitude of about , the largest mass apparently broke up in a violent explosion called an air burst. On November 20, 1957 the Soviet Union issued a stamp for the 10th anniversary of the Sikhote-Alin meteorite shower. It reproduces a painting by P. I. Medvedev, a Soviet artist who witnessed the fall: he was sitting in his window starting a sketch when the fireball appeared, so he immediately began drawing what he saw. Orbit Because the meteor fell during daytime, it was observed by many eyewitnesses. Evaluation of this observational data allowed V. G. Fesenkov, then chairman of the meteorite committee of the USSR Academy of Science, to estimate the meteoroid's orbit before it encountered the Earth. This orbit was ellipse-shaped, with its point of greatest distance from the sun situated within the asteroid belt, similar to many other small bodies crossing the orbit of the Earth. Such an orbit was probably created by collisions within the asteroid belt. Size Sikhote-Alin is a massive fall with the pre-atmospheric mass of the meteoroid estimated at approximately . A more recent estimate by Tsvetkov (and others) puts the mass at around . Krinov estimated the post-atmospheric mass of the meteoroid at some . Strewn field and craters The strewn field for this meteorite covered an elliptical area of about . Some of the fragments made impact craters, the largest of which was about across and deep. Fragments of the meteorite were also