We acknowledge the Hong Kong Collection (Hung On-To Memorial Library) of the University of Hong Kong Libraries for its contributions to this collection. The Hong Kong Collection (Hung On-To Memorial Library) of the University of Hong Kong Libraries has been actively collecting and organizing Hong Kong contents since the early 1970s. Staff members of the Library have contributed to the creation of the Collection by identifying and selecting pictures from the library collections, annotating the pictures, creating the indexes and deciding on the user interface of the database.