This happens in Mercenaries: Playground of Destruction. It may also be in World In Flames.
To observe this for more than a few seconds, one will need the infinite health cheat.
Go in any deep body of water and position the camera under the surface. Fog will stop rendering and things that are hidden behind the fog will be visible. It has to be something still relatively close because the fog is meant to be an optimization trick so the game has a lot less stuff to render at once.