Thessaloniki (Greek: Θεσσαλονίκη [θesaloˈnici]) is the second-largest city in Greece and the capital of Greek Macedonia, the administrative region of Central Macedonia and the Decentralized Administration of Macedonia and Thrace. Its nickname is η Συμπρωτεύουσα (Symprotévousa), literally "the co-capital", a reference to its historical status as the Συμβασιλεύουσα (Symvasilévousa) or "co-reigning" city of the Eastern Roman (Byzantine) Empire, alongside Constantinople.
The municipality of Thessaloniki, the historical center, had a population of 325,182 in 2011, while the Thessaloniki Urban Area had a population of 788,952. and the Thessaloniki Metropolitan Area had 1,012,297 inhabitants in 2011.
Thessaloniki is Greece's second major economic, industrial, commercial and political centre, and a major transportation hub for the rest of southeastern Europe; its commercial port is also of great importance for Greece and the southeastern European hinterland. The city is renowned for its festivals, events and vibrant cultural life in general, and is considered to be Greece's cultural capital. Events such as the Thessaloniki International Trade Fair, the Thessaloniki International Film Festival, and the Thessaloniki Song Festival are held annually, while the city also hosts the largest bi-annual meeting of the Greek diaspora. Thessaloniki was the 2014 European Youth Capital.
The city of Thessaloniki was founded in 315 BC by Cassander of Macedon. An important metropolis by the Roman period, Thessaloniki was the second largest and wealthiest city of the Byzantine Empire. It was conquered by the Ottomans in 1430, and passed from the Ottoman Empire to modern Greece on 8 November 1912.
Thessaloniki is home to numerous notable Byzantine monuments, including the Paleochristian and Byzantine monuments of Thessaloniki, a UNESCO World Heritage Site, as well as several Roman, Ottoman and Sephardic Jewish structures. The city's main university, Aristotle University, is the largest in Greece and the Balkans.
Thessaloniki is a popular tourist destination in Greece. For 2013, National Geographic Magazine included Thessaloniki in its top tourist destinations worldwide, while in 2014 Financial Times FDI magazine (Foreign Direct Investments) declared Thessaloniki as the best mid-sized European city of the future for human capital and lifestyle. Among street photographers, the center of Thessaloniki is also considered the most popular destination for street photography in Greece.