ATA was created on 18 June 1954. Since the end of the Cold War and the dissolution of the Warsaw Pact, the role of the Atlantic Treaty Association has changed considerably. In 1992, the ATA Constitution was amended to accommodate associate members and observers from non-NATO countries. In 1992, the Atlantic Club of Bulgaria joined ATA as its first associated member from a non-NATO country. Given NATO's shifting nature, ATA now works beyond the borders of the Euro-Atlantic, operating in Central and Eastern Europe, the Mediterranean, and the South Caucasus. Following the ascension of the new NATO countries in 1999 and 2004, ATA membership expanded considerably, and its security focus has shifted south and eastward.