The Women's march on Versailles was caused by the poor economy of France at the time. The most common food, bread, was skyrocketing in prices which made the people angry, especially the wives that bought food to their families. They protested the prices by marching to Versailles and demanded the King to come to Paris.
After being forced to return to Paris the King struggled to fit in and received little support. The king was so distraught that he tried to escape along with Marie Antoinette. They were recognized and arrested, and the news of the king trying to escape killed all of his credibility to the people of France.
The Guillotine was an execution used by the french during the French Revolution. It was thought to be a more humane way of execution that was mostly painless. During the Reign of Terror, it is thought that 40,000 were victim to the guillotine.