What kind of crowbar to use to open a manhole?

Tom S has the answer. If the manhole is stuck to the rim with debris, it can be loosened by beating on it with a hammer. The hammer blows will loosen the debris and make it vibrate up a bit to ease pulling the lid. This is the only way to do it if the rascals at public works have sprayed road oil into the crack around the rim. Use a hook. Crowbars are dangerous.