What factors brought about the end of communism in Eastern Europe and the Soviet Union?

The Soviet Union experienced a crisis due to economic waste. The socio-cultural crisis in the USSR occurred because of class division, the low quality of people's lives, and the government was not allowed to develop people's creativity. In particular, the system named Glasnost and Perestroika which was proclaimed by President Gorbachev was the trigger for the explosion of social revolutions in Eastern European countries.

ww1 weapons: tank. tanks were used for the first time in the first world war at the battle of the somme. they were developed to cope with the conditions on the western front. the first tank was called 'little willie' and needed a crew of 3.