African trypanosomes (15-20 µm long, turquoise), which are responsible for human sleeping sickness in Western and Central Africa, are shown here intertwined with red blood cells (5 µm, red) in a blood capillary (green). The structural and physiological beauty of these protozoa sometimes make us forget the deadly package that they harbor. At the peak of the infection, the parasite density is upwards of several million trypanosomes per milliliter of blood; this image clearly portraits the difficult relationship between the parasite and the human immune system. Studying this relationship has been the subject of my group’s research for many years at the Université Libre de Bruxelles (ULB) in Belgium. Recently, this led us to engineer therapeutic proteins that kill pathogenic trypanosomes in vivo (see Fontaine et al. Nature Microbiol. 2017; 2:1500-6). Trypanosomes have been engaged in an evolutionary arms race for thousands of years in Africa, thereby shaping our own stronghold of immunological defenses and fundamentally impacting human evolution. Our team at the electron microscopy facility has worked on dozens of subjects over the years, but trypanosomes are still one of our favorites. Daniel Monteyne, Ariel Talavera, Marjorie Vermeersch and I (below, right to left) probably have one of the nicest jobs on earth, looking into infinitely small wonders. We marvel, each time, at how much detail we as a species can now see after starting with just our curiosity and a few stone tools.