The New England Patriots wear the black number 91 to honor their teammate Marquise Hill who died in a drowning earlier this year in May.
In 2007 Sean Taylor(Washington Redskins) was murdered and teams put a black circle with a white number 21 in it in tribute to him.
Pat Tillman played for the Cardinals and was a US Army Ranger. He was called to serve his country in Afghanistan, and was killed while on duty. The NFL decided to honor his memory by having each player wear a #40 sticker on their helmets.
Black Circle was created in 1915.
The Black Circle has 178 pages.
San Diego does have the black 21 on their helmets.
The black dots on a map represent cities.
It isn't 12, it is 21 currently-and that is for Sean Taylor the Redskins Safety that was killed earlier this year.
The People of the Black Circle was created in 1974.
The Black Circle was created on 2009-08-11.
Black represent the black people/humans in south africa