How well do you know NCIS? Take our quiz and find out

NCIS celebrated its 450th episode in February, which means that amid 20 seasons of terror plots, assassination attempts, and murders both at sea and on land, we've had oodles of time to get to know the people who've come and gone from the big orange room at the heart of the Navy Yard headquarters.

The show premiered under the steely gaze and quiet grit of Leroy Jethro Gibbs (Mark Harmon) —and under the redundant title Navy NCIS: Naval Criminal Investigative Service — in 2003. Since then, it's expanded to welcome an ever-changing roster of agents, scientists, and doctors, all of whom are committed to solving crimes involving the U.S. Navy and Marine Corps.

With two decades stretching between the premiere and today, even diehard fans may be surprised by how many details they remember — and how many they've forgotten. How well do you know your "Yankee White" from your "Truth and Consequences"? Get your McGeek on and take our quiz below.

Related content:

• Sean Murray talks NCIS longevity and saying goodbye to Mark Harmon as the show hits 450 episodes
• The 25 essential NCIS episodes
• Pam Dawber on her NCIS debut: No, she didn't join to be a love interest for Gibbs