In 1989, the Berlin Wall was opened, the Soviet Union collapsed, and East Germany was reunited with West Germany in 1990. In 1998–1999, Germany was one of the founding countries of the eurozone. Germany remains one of the economic powerhouses of Europe, contributing about one-quarter of the eurozone's annual gross domestic product. In the early 2010s, Germany played a critical role in trying to resolve the escalating euro crisis, especially concerning Greece and other Southern European nations. In the middle of the decade, the country faced the European migrant crisis as the main receiver of asylum seekers from Syria and other troubled regions.