Fabian Zimmer recounts a childhood visit to the Schwarzenbach Dam in the Black Forest in southern Germany on a public open day as a way into considering how dams have been portrayed by hydroelectricity companies. Having gone from being a dam spectator to an observer of dam spectators, Zimmer discusses how the perceptions of dam visitors have been actively shaped by public open days, with many holding high hopes of a future driven by hydroelectricity throughout the twentieth century.