British scientist James Smithson left a fortune to the country he so admired but had never visited. His gift founded the Smithsonian Institution and built the Smithsonian Castle. Today, the castle's distinct Romanesque facade glows warmly against the cool marble that dominates the National Mall. Yet the story of the stones is just as remarkable as that of the building that they grace. It was a boom-bust ride for the Seneca Quarry—the source of the red sandstone. The quarry saw its first developer die, filed for bankruptcy twice, suffered through floods and contributed to a national scandal that embarrassed the Grant presidency and helped bring down the Freedman's Bank. This is the untold history of the quarry owners and emancipated slaves who toiled there and the many people who work to this day to save Seneca. Join author Garrett Peck as he traces the unlikely story of the Smithsonian Castle and the Seneca Quarry.