In the Battle of the Marne, the German troops tried to take Paris, France ASAP. The First Battle of Marne started in 1914 and ended as a stalemate. The Second Battle of the Marne was on 1918 which also ended as a stalemate. The first set of the two was the first major battle in World War I.
The French used "trench warfare" to try and slow the Russian advancement to Paris. There were mines, barbed wire, machine guns, and massive troops protecting the trenches.
Trench Warfare was something that was very miserable. This type of warfare had bad living conditions for people who lived in it. Troops were stationed and kept there. Food was scarce, water was bad, and everyone was dirty. Many died from the harsh conditions of Trench Warfare.