Petard

A petard is something that people used during old times to blow up doors or walls. It's like a special kind of bomb that they put on a gate or a wall and then lit a fuse, which caused the bomb to explode and break down the barrier. It was a way for soldiers and spies to get into places they weren't supposed to go, like enemy castles or secret hideouts. It was a very powerful and dangerous tool to use, so only very skilled people were able to handle it properly. Nowadays, we don't use petards anymore because we have much safer and more advanced techniques to break down doors and walls.