Protesters formed 'a human chain' [=they stood next to each other with their arms linked] around the ancient tree to prevent it from being cut down.
In the United States, the President as the commander in chief is at the head of the military 'chain of command'.
I thought he really won the lottery but he was only 'pulling my chain'. [=he was only playing a joke on me]
(..) Nice tattoo. Manolo, make that two. - What's that for? - Can't afford to catch cold. First you find out where the chain is. You can't see it, but you can feel it. Here. - I'll ring, you start talking. - What do I say? Whatever you want. (..)1994 Léon: The Professional