The peace treaties that ended World War I were the Treaty of Versailles (with Germany), the Treaty of Saint-Germain (with Austria), the Treaty of Trianon (with Hungary), and the Treaty of Neuilly (with Bulgaria). These treaties were very harsh on the defeated Central Powers, and they contributed to the rise of nationalism and revanchist sentiment in Germany and other countries.
The peace treaties also failed to address the underlying causes of World War I, such as the arms race, imperialism, and the secret alliances between European powers. As a result, these factors contributed to the outbreak of World War II just 20 years later.