Alexis Chappuis is a French marine biologist, National Geographic Explorer, and technical scientific diver working in Indonesia since 2014. In 2018, he founded UNSEEN Expeditions, an NGO focusing on exploring and documenting mesophotic coral ecosystems – at depths of 100 to 160 metres – in Southeast Asia, particularly Indonesia. Believing that we best protect what we know, Alexis's work involves collaborating with local and international scientists to study these poorly known and poorly protected deep-reef habitats, using closed-circuit rebreathers. Images play a crucial role in his expeditions, showcasing the unseen and the unknown. Driven by genuine curiosity, Alexis’s efforts aim to improve scientific knowledge and raise awareness about the importance and urgent necessity of marine conservation in a context of dramatic biodiversity decline and destruction of natural ecosystems.