Imaging Blood vessels provide nutrients and oxygen to organs, and changes to the vasculature during aging are expected to contribute to organ function decline. Chen et al. performed a comprehensive analysis of tissue-specific vasculature of young and aging mice using high-resolution three-dimensional (3D) imaging of organ-specific vascular beds, with validation in human samples. They found evidence of capillary and artery loss in the early stages of aging, preceding senescence, in a tissue-specific manner. Vascular alterations precede cellular aging hallmarks, suggesting that vessel loss is a primary trigger for aging. These high-quality 3D maps of vascular microenvironments will be a crucial resource for the scientific community. Sci. Adv. 10.1126/sciadv.abd7819 (2021).