Thessaloniki, the second largest city in Greece, is a cultural and historical destination of great importance. Founded in 315 BC. by Cassander, has been a communications hub between the West and the East for centuries. The city has been influenced by various civilizations, including Macedonians, Romans, Byzantines, Arabs and Ottomans, which is reflected in its rich architectural and cultural heritage. Thessaloniki is known for its ancient buildings, churches, monasteries and mosques, some of which are UNESCO World Heritage Sites. The city also houses important museums that tell its ancient history. In the 20th century, Thessaloniki suffered a major fire in 1917 and was liberated from the Ottomans in 1912. Today, it is a commercial and business center, and its International Fair is one of the largest in Greece. The city has a population of approximately 800,000 inhabitants in its urban area and more than one million in its metropolitan area.