When my friend and I were coming back from e-mart we passed the some apartments and we were passing CCTV room and the door was opened. And when we were passing it, the door closed on its own even if it wasn't windy! And if a person closed that his or her hand would be seen but there wasn't even person in there! If someone was just attaching a string it would have been seen too. But there was't anything! So my friend and I ran for our lives.