Chris Lavelle for AEtuts shows how to create an infinite ground plane in After Effects with a lava scene where the camera appears to continuously travel.

“Hey there, how about a real world solution to a problem? I recently had a brief where I had to have a camera traveling along a cracking road with lava filling the cracks with periodic lava spurts. Now this is very doable in a 3d package but I decided to try and do it in AE alone. This is what I came up with….
Now, this video had to last 4 mins, so traveling a camera along a path for 4 mins is just too much z space to work…. So using a few expressions and a recurring null i managed to create a base (which could be used for anything really) that continuously travels and by parenting objects to the traveling null we have the effect of objects moving toward the camera. This template works for many ideas…. maybe even a guitar hero animation.”