The structure and organisation of a eukaryotic cell dictates its functions. This leads to the tremendous diversity we see  in cellular architechtures across the eukaryotic tree of life. I study single-celled eukaryotic parasites including Plasmodium, the cause of malaria, and Cryptosporidium a significant pathogen of humans and livestock. These parasites infect half a billion people annually, and current treatments to stop disease are either losing efficacy, or cause significant side-effects. These parasites have specialised lifecycle stages for invading their host cells, called zoites. Zoites are highly structured and polarised, with their apical end containing all the organelles required for host cell invasion. For most of their lifecycle, however, these parasites are not highly organised and lack obvious cellular polarity. Through my research we aim to understand how these parasites create order from disorder. We use cutting-edge microscopy approaches to visualise parasites, observe how they build their highly organised zoite stages, and investigate what happens when we perturb key regulators of these processes. These insights are key for understanding basic parasite cell biology, and may unlock avenues for development of novel antiparasitc therapeutics.