The euro is the new currency for many Europeans. 11 September 2001 becomes synonymous with the 'War on Terror' after hijacked airliners are flown into buildings in New York and Washington. EU countries begin to work much more closely together to fight crime. The political divisions between east and west Europe are finally declared healed when no fewer than 10 new countries join the EU in 2004, followed by two more in 2007. A financial crisis hits the global economy in September 2008, leading to closer economic cooperation between EU countries. The Treaty of Lisbon is ratified by all EU countries before entering into force on 1 December 2009. It provides the EU with modern institutions and more efficient working methods.