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]
(..) on our own ship, sir? I'd rather see her at the bottom of the ocean than in the hands of a pirate. Commodore, he's disabled the rudder chain, sir. Abandon ship! That's got to be the best pirate I've ever seen. So it would seem. WILL: When I was a lad (..)2003 Pirates of the Caribbean: The Curse of the Black Pearl