The seaweed revolution is a fresh hope for tomorrow. Seaweed develops in water everywhere, from the eternal glaciers to lagoons heated by the sun, from seas saturated with salt to the fresh water of our rivers. Yet we only know how to cultivate a few dozen varieties, at most. Incredibly diverse, seaweed could help to bring back balance in our ecosystems through a wide range of applications. It could allow us to better feed human beings and animals, replace plastic and fertilizers, boost medical innovations, mitigate global warming, repair biodiversity and support economies in coastal communities where fish stocks are declining. Although seaweed has supported our development for millions of years, we have lost our connection with it and focused our efforts purely on land cultivation. Today a fast-growing global population, combined with climate, social and environmental crises, gives us compelling reasons to reconsider this forgotten treasure.