Figure 15.4. London's Millennium Dome (now known as the o, Arena) was open to the public as an exhibition for just one year in 2000, but to be a Against forecasts of 12 million paying visitors, only about half this figure actually visited. Forecasts were made difficult because of so many uncertainties in the business environment and the absence of comparable previous projects, which might give some idea of the likely take-up. disappointment in terms of visitor numbers