FM radio antenna

It's embedded in the rear window just like the rear window defroster. Look close, you will see extra wires separate from the defroster up high, where the defroster doesn't heat. The one on the roof is the phone and satellite radio shark fin. Even if you don't have those options you still get the shark fin.

its under the car near the muffler

either on the roof or under the hood

its on the roof on the back of the roof.it doesn't really look like an antenna
its like a hat looking.its not a long medal steel sticking out.

its either on the roof it looks like a sharks fin or its built into the back window.