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]
(..) And that's where you're headed. A billion-dollar valuation. Unless you take bad advice, in which case you may as well have come up with a chain of very successful yogurt shops. When you go fishing, you can catch a lot of fish or you can catch a big fish. You ever walk into a guy's den and see (..)2010 The Social Network