Professional sports facilities are among the most expensive development projects. Assessing the external effects related to these and the channels through which these effects operate is a challenging task. We propose a strategy to value the external effects that stadia deliver to their neighbourhoods based on the variation in property prices. Our strategy allows for unobserved spatial heterogeneity, anticipation effects, and disentangles the stadium's function as a sports facility from its form as a physical structure that (visually) dominates the neighbourhood. We apply this strategy to two of the largest stadium projects of the recent decade, the New Wembley and the Emirates Stadium in London. Our results suggest that there are positive stadium effects on property prices, which are large compared with construction costs. Notable anticipation effects are found immediately following the announcement of the stadium plans. We further argue that stadium architecture plays a role in promoting positive spillovers to the neighbourhood.