The wall separating the Whampoa street buildings and Whampoa dock. Those buildings were built around 1957. The shop with the orange shop sign later became the shi sun fast food restaurent. (https://www.hk01.com/%E7%A4%BE%E6%9C%83%E6%96%B0%E8%81%9E/111809/%E6%99%...)
More exactly the restaurant started out as a store selling snacks, drinks, cigarettes etc around 1965. It was the shop with white sign on the right hand side of the shop with the orange sign. Later after 1976, they became a fast food restaurant by taking over its neighbor with the orange sign. It is because this picture was taken in 1976 before the transition.
Before that the Whampoa street didn't even exist and I wonder if the wall was even necessary.
The North point and Wanchai piers were on the right out of the picture. The piers were built in 1963. Part of the wall is still visible today: