Warsaw is the leading economic and financial hub of Central Europe, the Visegrád Group and the Three Seas Initiative. In 2019, the city's Gross Domestic Product (GDP) was estimated at €94 billion ($ billion), which places Warsaw among the wealthiest regions in the European Union; it generates approximately 1/6 of the total GDP of Poland and the country's national income. In 2020, Warsaw was classified as an alpha world city (also known as a "major global city that links economic regions into the world economy") by the Globalization and World Cities study group from Loughborough University, placing it on a par with cities such as Sydney, Istanbul, Amsterdam or Seoul.