Bipolarity, or the presence of the same species in both polar regions, has intrigued the scientific community over centuries. Almost the entire tree of life taxa, from microbes to whales, are known to include some bipolar representatives inhabiting the Arctic and the Antarctic. However, our knowledge on the evolutionary origin and consequences of bipolarity are still fragmentary. POLE2POLE will focus on Hydrozoa (Cnidaria) as a model group to unveil bipolarity patterns and processes with a multi-scale methodology. Given their ubiquity and the wide array of life cycle strategies, hydrozoans constitutes the ideal system to asses this natural phenomenon, enabling a comparative approach. I will first perform an integrative species delimitation on selected hydrozoan taxa representing major ecological and life cycle strategies. I will then reconstruct the evolutionary history of the selected cases by means of High-Throughput Sequencing techniques. Time of divergence and character evolution will be subsequently estimated for the taxa analysed. The project will allow to determine if the divergences took place during an interglacial period or during a glacial maxima, and therefore if vicariance and/or dispersal respectively shaped the current distribution of bipolar hydrozoans, and if previous hypothesis on the presence of relict taxa can be corroborated. Furthermore, POLE2POLE will allow to study in an unprecedented way if life cycle strategies and their corresponding dispersal capabilities are linked with time of bipolar divergence. Thus, through POLE2POLE, I will develop a novel transversal and interdisciplinary framework to study the origin and diversification of the biota inhabiting polar regions, and a model system for speciation processes over oceanic scale. The project will be implemented at University Museum of Bergen (UMB-UiB) under the supervision of Dr Aino Hosia.