How Do You Activate the Halo 3 Recon Skull On Floodgate?

To activate the Halo 3 Recon Skull on the Floodgate level, first, complete the mission until you reach the area with the large floodgate. Look for a small ledge on the left side of the gate, which can be accessed by jumping from the nearby structures. Once on the ledge, you'll find a series of symbols that you need to interact with in the correct order to unlock the skull. After activating the symbols, the Recon Skull will appear, allowing you to collect it.