It's usually not good to discover rats' nests in your walls, but a serendipitous turn of events in Charleston has revealed what a treasure they can hold. It began when sunlight bouncing off a door in her office in the kitchen house of the 1808 Nathaniel Russell House prompted Lauren J. Northup, director of museums for the Historic Charleston Foundation, to speculate that perhaps the door was original to the structure. The ensuing investigation revealed that her hunch was right and, in fact, that some 85 percent of the original building fabric survived behind and beneath twentieth-century flooring and drywall. In the process of removing the later materials, the bits and pieces scavenged by rats and built into their nests, amazed the team. As Northup says, "we have now learned more about the life of the enslaved people than is known about the white family."