On the roof of the Union Square shopping mall, three storeys above the ground, is a pseudo ground level public place with walkways, gardens and a central plaza surrounded by outdoor cafés and bars. Entrances to the various building complexes of Union Square are located on this level. Although Union Square was conceived as an interconnected space centred on transport infrastructure, it was criticised in a 2013 University of Hong Kong study as being cut off from its surroundings, especially for pedestrians. Paul Zimmerman said Union Square is "an island of the rich disconnected from its surroundings", and a lesson for future urban planners. This concern is shared by Farrell, who said there were pre-determined site constraints, and little could be done to mitigate them.