How did the fall of Bastille prison become the immediate cause of French Revolution?

How did the fall of Bastille prison become the immediate cause of French Revolution?
Answer:
On the morning of 14th July, 1789, the city of Paris was in a state of alarm. The king ordered his troops to move into the city. Rumours spread that he would soon order the army to open fire upon
the citizens. Some 7,000 men and women gathered in front of the town hall and decided to form a people’s militia. A group of several hundred people marched towards the eastern part of the city and stormed the fortress-prison, the Bastille. In the armed fight, the commander of Bastille was killed and prisoners released. Since the Bastille stood for the despotic power of the king, it led people towards the success of French Revolution.