NATO has been called the most successful alliance in history.
The organization celebrates its 70th anniversary on April 4. On that day in 1949, 12 nations signed the North Atlantic Treaty, establishing NATO and ensuring years of peace in Europe.
The United States has been a mainstay in the alliance since its formation. At the height of the Cold War, there were more than a million American service members in Europe helping ensure the peace.
Through the rise and fall of the Berlin Wall, American soldiers, sailors, airmen and Marines and their civilian counterparts have given Europeans the gift of stability.