The North Atlantic Council convenes in the Mellon Auditorium in Washington, D. C. The North Atlantic Council convenes in the Mellon Auditorium, Washington, D. C., on April 24, 1999. This historic site was chosen as the location for the 50th Anniversary NATO Summit because it was here, on April 4, 1949, that the North Atlantic Treaty was signed. The resulting institution, the North Atlantic Treaty Organization, has become the most successful alliance in modern history. SHARE: Download: Full Size (0.07 MB) Credit: VIRIN: 179762-P-KXR62-199.jpg Photo Gallery