The Angel Strikes Again - Lily Ho (1968) - Anderson Road Quarry

The gang's secret hideout is hidden behind a quarry wall and hidden by a secret door. In this case we can see it is the Anderson Road quarry, although in the 1960s it still consisted of several smaller quarry faces.

We know we're here because of the views to to background behind the actors. In the top image, as the guy is about to blow up the secret door, we can see the north side of Hong Kong Island behind him. In the second image of 009 and the local police detective, that ridge in the background is Black Hill. You can walk along there on Stage 3 of the Wilson Trail if you ever feel the urge.

Looking at old maps, it looks as though the quarry face where this was filmed was located at what is now immediately east of On Kin Road near On Sing House.