This article is devoted to the research of the reasons behind the occurrence of the crisis in Greece and challenges and opportunities that arise both for the global economy and the economy of the European Union (EU). The theme of the article is rather urgent by reason of incomplete understanding of the nature of the crisis in Greece, its suddenness and impossibility to predict its consequences for the global economic relations. The main goal of stating the materials in this article is to analyze the reasons of the crisis in Greece in terms of economy, history, sociology, and other scientific areas. Basic tasks include the following: To reveal a complex of all aspects of the economic crisis in Greece, to analyze its deep (historical) reasons...