This is a short clip from 1986 featuring a Soviet ICBM called the SS-18 "Satan". This was technically the second version, and the system was being qualified with its first live launch from a silo. The SS-18 is "cold launched" which means it is stored in a silo, but a tiny explosion inside the silo is intended to fling the missile up into the air before its engines turn on. This greatly reduces the wear-and-tear on both the silo and the missile, since the heat and acoustic damage from a full-on rocket engine is really hard to design for.
The way this is supposed to work is that the missile's guidance system and accelerometers are supposed to be running when you pop it out into the air, and when the guidance system detects that it's starting to fall backwards, it lights the engines and flies away. In this case, that did not happen.
Instead, a 3m x 25m cylinder full of really dangerous flammable chemicals - which are designed to explode when mixed - fell from a great height into the silo, consuming all of the fuel and oxidizer in an instant. Nothing remained except a crater.