When I was trying to get the IWHBYD skull I fell and I ened up in a garage and when I steped out I was walking on nothing! First I was walking on buildings and I got to the pelican checkpoint (Where if your trying to get the skull you jumpp down on the ramp to see the pelican fly away) there is a small space between the building your trying to jump to and the rail. Fall in the space and keep on walking.You should end up in a sort of garage.

Sign on Zanzibar
On the beach on Zanzibar, you will see signs that say NO SWIMMING. Well, go to your xbox dashboard, go to the Settings, Clock, and change every number you can to 7 , then pop Halo 2 back into your xbox and load it up. WARNING: Do not sign into XBoxLive, it resets your clock. Now go to Split-Screen and start a game on Zanzibar. Go to the beach and look at the sign, it will mention something is missing, and there is a bloody dog's head.

First go to Quarintine Zone. Next look around to your right side and you should see a small tunnel. Walk through it. Now keep on going strait till you see a strip of land that is connected to the wall (There are many strips of land connected to the wall so pick the one that has kind of like a part of a ship or metal hiding it). Walk down the strip of land ( careful not to fall off ) till you reach the end and you should see a floating skull. You must do this on Legendary.

This skull makes things have bigger explosions and more
powerful melee attacks.

When you crash on the level Outskirts step outside and you will see a grunt, kill him. Now look up to you right and left side. You will see two lights. Jump on one and grenade or crouch jump(grenade jump is a little hard on a light)up on the roof. Look around and you will see a small dark pathway. Walk down ithe path and you will find a skull and a couple frags. Pick up the skull and your HUD will disapear. Do this on any difficulty.