These are the consequences of the use of an alternative to napalm by Russsian
army back then. It was done as a test inside of the brick houses. The temperature was so high that it made bricks to melt and form such icicles.
Russian fortress is one of the creepiest places we’ve seen. The reason it looks this way is that the Russian army used the abandoned fortress to test the influence of Russian alternative to napalm inside of the brick houses. Due to very high temperature of napalm the bricks started melting just like ice melts in the spring forming the icicles, however these icicles are made of red brick.