'NCIS' trivia and fun facts

The hand tools that Mark Harmon uses on the set of NCIS are mostly his own. Those are the tools that he uses in his own personal workshop.

Producers have said that most of the personality and interests displayed by Abby come from Pauley Perrette just playing herself. She is graduated in Forensics before coming to 'NCIS'.

The sound heard at the beginning and end of each act, when the scene goes to black and white is Donald P. Bellisario making that noise into a microphone. He wanted a unique way of bookending each act.

Jethro Gibbs's father Jackson Gibbs (played by Ralph Waite ) was a World War II US Army Air Force fighter pilot, as was Mark Harmon's real life father Tom Harmon.

In addition to Troian Bellisario, one of Donald P. Bellisario's children, who plays as McGee's sister, there is also one of his sons, Michael Bellisario, who played Charles (Chip) Sterling on the show.

There is a picture of Donald P. Bellisario hanging on the "NCIS Most Wanted Wall".

Whenever we see flashbacks featuring young Gibbs, the younger version is played by Mark Harmon's son, Sean.

A satellite image of the Santiago Bernabeu Stadium in Madrid sometimes appears on Gibbs' computer.