The North Star Mixed-use Development in Beijing has two towers. The office tower more than 100m high, guards an innovative, popular six storey shopping podium which sits on two levels of basement car parking.North Star liked the design from the first day. So Aedas had two or three design meetings and hardly any other involvement from the company. But there was agreement about the symbolism.The façade and the glass portions of the building are exceptional and this fact has sometimes led us to use glass more than we normally would. In a place like Beijing there is pollution in the air which is easily cleaned from glass. But glass is very economical from a maintenance point of view. Its use diminishes heating and energy loads including artificial light. The tower façades on this scheme are in insulated glass with Low-E coating and the podium's laminated glass with reflective coating is used to reduce solar heat gain.As is the frequent case with new buildings in China the scheme has its own well understood symbolism and the client liked the symbolism of water.The controversial geodesic glass roof reaches high over the middle of the podium and cascades down between glass bluffs like a waterfall above the entrance doors through whose lower reaches people come and go. Water stands for money and cascading water stands for cascading money to the credit of the owners and tenants and presumably to the customers.A six-level shopping mall represents new thinking about the nature of shopping. The Western view is that two floors are around the maximum for good retail interaction. And the snaking of the geodesic skylight across the roof of the podium has a very real function. Its extent is essential because without a generous clear glass ceiling it would be difficult for light to penetrate down six floors through the voids in each floor level to ground level.One of the points of having access to all sides of the mall was that a railway station was scheduled for the north side of the development and the point of the design was that people would come out of the station and go straight into the mall. The whole design was about bringing that energy into the shopping mall.The interior is a complex arrangement of aerial walkways and of bifurcated vistas as the different islands and coves of the plan come into view of the pedestrian shopper.The exact route to a particular shop is not always immediately apparent so that searching for it involves exploring, drifting past rivals and certainly purveyors of alternative products in which the shopper may become interested. The experience of North Star is surely to do with serendipity which is one of the sources of the pleasure of shopping.