Last month, there was an unanticipated archeological discovery under the National Mall as part of the @smithsonian Castle Revitalization Project. The Smithsonian Castle, which opened in 1855, was part of the effort to make the city’s infrastructure more functional and self-sufficient. In the absence of modern piping, cisterns like the one discovered beneath the Castle were a standard solution for storing rainwater. In the case of the Smithsonian Castle, the discovery of the cistern highlights the importance of preserving the stories these structures tell about the city’s past. The find has not halted the renovation of the Castle but has added another layer of history to the project.