Bacteria Nanowires
Shewanella bacteria roughly 1/50th the width of a human hair reach out nanowires to breathe when deprived of oxygen. These types of bacteria are typically found underground or in lake or ocean sediments, where oxygen is scarce.
Credit: Clips from "Shewanella oneidensis MR-1 nanowires are outer membrane and periplasmic extensions of the extracellular electron transport components," El-Naggar et al., PNAS 2014 DOI number 10.1073/pnas.1410551111