Fashionistas are breathlessly speculating about what Michelle Obama might wear for the inaugural ball on Monday night. In honor of this historical sartorial occasion, TIME took a look at some of the dresses First Ladies wore to celebrate this same occasion over the centuries. The Smithsonian Museum of American History houses a nearly 100-year-old exhibit dedicated to just such artefacts. Curator Lisa Kathleen Graddy led us on a tour and even gave us a look at some gems stored in the back rooms (like Mamie Eisenhower’s iconic pink number). “She is a figure that is at the same time familiar and remote,” Graddy says of our First Ladies. “She’s our national representative. She’s the soft side of the Presidency.” And Americans want to know: whatever did they wear?