The introduction of the euro currency in 2002, the enlargement of the European Union in 2004 (the accession of Poland, the Czech Republic, Slovakia and Hungary) and 2007 (Romania and Bulgaria), the attempts to agree on a response to global warming, the record level of investment transactions in Eastern Europe in 2006, the global financial crisis after the collapse of Lehman Brothers in 2008, and the crisis in the countries of the eurozone - these are a few of the last ten years' ten macroeconomic events that have had the biggest impact on the economy and the property market in Europe, according to Colliers International.