KANSAS CITY, Mo. — The Kansas City Chiefs are doing something special to honor the legacy of late Chiefs legend Derrick Thomas and his father.

On Sunday, the Chiefs will wear a patch to commemorate the 50th anniversary of Operation Linebacker I & II, a military operation during the Vietnam War that claimed the life of Derrick Thomas’ father U.S. Air Force Capt. Robert Thomas and many other soldiers.

This is part of the NFL’s yearly Salute to Service initiative. The 50th anniversary of the mission also parallels the 50th anniversary of Arrowhead Stadium.

Operation Linebacker I & II was the U.S. strategic bombing campaign in 1972 designed to bring the North Vietnamese government to the negotiating table.

Capt. Thomas’ B-52G heavy bomber was shot down on December 18, 1972.

The Chiefs will have a shadow box that honors both Thomas’s at one of the franchise’s properties.