The group of Chiara Zurzolo studies the function, structure and formation of tunneling nanotubes (TNTs) that connect neuronal cells (Gousset et al., 2009; Nat. Cell. Biol. 11:328; Delage et al., 2016; Sci Rep 6: 39632). We characterize TNTs at the ultrastructural level and describe their structural identity using correlated light- and cryo-electron microscopy approaches and FIB/SEM methods.