NM 597 is a short spur from US 160 leading to the Four Corners where four states meet. I suppose this couldn't be called NM 4 since there's an NM 4 from US 550 to NM 502 east of Los Alamos.
This photo was taken in May 2004, looking toward the entrance to the Four Corners monument, operated by the Navajo reservation's parks and recreation department.