Answer based on context:

The 49ers played their final regular season game at Candlestick Park on Monday, December 23, 2013 against the Atlanta Falcons. Their 34-24 victory came after an interception by NaVorro Bowman with 1:28 left in the game. The play would seal a win for a playoff spot for the 49ers and is called The Pick at the Stick by some sports columnists. This game was also Candlestick Park's 36th and final game on Monday Night Football, the most at any stadium used by the NFL.

Which sports organization was conducting this game?
NFL