It seems that the fruit is really called "Dragon Fruit", after 2-3 URHK readeres have emailed me. I have been told there is no official name of this fruit in the western world. Thanks everyone for your input. I appreciate it.
Some URHK reader asked me where I took this picture.
The place is called "Kam Tin" - part of New Territory. However, don't consider coming to this place, in search for a picnic or a bicycle ride; you will be disappointed, unless you have a special taste. The smell around this area is pretty bad because a drainage is right beside where the picture was taken. ;)