If you are in delta halo ,after that bit when you lower the bridge ,go to the bit straight after the bit with the bridge (the one with a the pool and lots of energy shields arround the place) ,get a ghost and drive up onto the rock mountain wall (the one that's on the right). The wall looks pretty vertical and steep ,but if you use that nitro thing on the ghost you'll make it up and onto the wall. If you can't get up on the wall ,try and get up on the wall from different angles. When you're up on the wall ,turn left and drive on for a while. You'll find different levels from the game all over that "mountain range". You'll also findthat you'll be able to get to the other side of that big lake ,cuz it wasn't even programmed to be filled with water. You'll be able to just drive right through the "water" to the bottom of the lake (which is just like a giant field) ,you'll also notice that all the buildings on the "lake" are actually just floating. But BEWARE!!! ,when you are trying to get down to the "lake" ,pick a bit of the mountain which isn't steep cuz if it is ,when you'll try to drive down to the lake you'll die and have to start all over ,(basically ,just drive slow of an even hill). NOW THAT'S WHAT I CALL A GLITCH!!!!!!!

Yeah I have done that with a ghost, pretty neato going around the whole level, especially when your bored like I was that day