In the scene where Lee goes to his mother's grave to beg forgiveness for his impending resort to extreme violence, the Muslim Cemetery was used to as the location for this scene. Like many other places of religious and/or spiritual significance in Hong Kong, the place has managed to stay fairly untouched over the years.
The location used is on the very top tier of the terraced cemetery and offers some great views over the racecourse and surrounding area. Here is what it looks like today. Look carefully and you will see many of the same headstones.
And in case you were wondering what is written on the front of the gravestone Bruce was looking at, here is a snap of the front. So now you can see what Bruce was looking at all those years ago.