The Treaty of Versailles is known for being very harsh on Germany, but it officially ended World War I. This treaty put the complete blame on Germany for the war, while Germany felt it wasn't all of their fault.
The Treaty of Versailles basically made Germany accept the responsibility and the war damages for World War I. This caused Germany to disarm, pay very large sums of money, and give up land such as France. Their army was now limited, they could not have tanks or military aircraft, and were limited to only 6 battleships. This obviously angered Germany quite a bit.
Eventually, Germany got fed up with the Treaty of Versailles and started to violate it, which eventually lead to World War II. Hitler did numerous things to violate the treaty, one of the first occurrences was by sending troops into Rhineland, which was demilitarized at the time. He also stopped paying reparations and started rebuilding the German military which was a direct violation of the Treaty of Versailles.
