Hierarchical structures appear often in life and materials sciences, and their characterization profits greatly from imaging methods that allow seamless probing of various length scales without sacrificing image quality. X-ray tomography is particularly adept at probing 3D structures; however, zooming in on a region of interest results in a loss of quantitativeness of image contrast and suffers from artifacts unless a priori knowledge or assumptions about the sample are used. Here, we demonstrate a hybrid technique that exploits a micrometer-resolution overview to realize ab initio nanoscale interior tomography with quantitative contrast. In a study of avian eggshell, a model for bionanoporous materials, our approach reveals a complex arrangement of vesicles with sizes ranging from hundred nanometers to a few micrometers. We anticipate that such an approach can be widely adopted and benefited from at synchrotron and laboratory sources, for instance, where such zooming capabilities are already present or can be readily realized.