This square is the one of the most famous spots in Paris. Although today a notoriously busy place for traffic and, especially, fast drivers, it marks the place where the Bastille fortress was built by Charles V in the 14th century to serve as a fortress protecting the city during the Hundred Years' War. It's fame as prison comes from the storming of the Bastille on July 14, 1789 which marked the beginning of the French Revolution. Destroyed at that time as a symbol of repression, the bronze column standing on the site today depicts the Angel of Liberty.
July 14th is now the Fête Nationale, a French national holiday.