Today track and field athletics takes place at the open-air Alexander Stadium on a national and international level. Recent development has seen addition of a High Performance Centre for indoor intense specialist training. The Stadium is also home to Birchfield Harriers, who have contributed towards Britain's National and International Athletics for many years and has produced international athletes such as Denise Lewis, Mark Lewis-Francis and Kelly Sotherton. The National Indoor Arena is Britain's Premier Indoor Athletics stadium and in 2003 hosted the 9th IAAF World Indoor Championships in Athletics. The city hosted the European Athletic Association's 2007 European Athletics Indoor Championships.