Seaweeds are multi-cellular macroalgae that, together with unicellular forms, all perform photosynthesis and are the foundation of the Earth's food web. Together, they are responsible for a major part of organic production on the planet. The algae produce essential macromolecules that are the constituents of our food, which are then funneled through various trophic levels of the food web and may end up as human food. Due to their abundance in all climatic zones, their diversity, and their availability along most coast lines, seaweeds have, since primordial times, been intertwined with human lives and development both as sustenance and as a material that has served a multitude of purposes for human activities. This chapter provides a brief sketch of the history of seaweeds as a food for humans and links their unique properties to the evolution of the human brain, to human health and wellbeing, to being a savior in times of famine, and to providing a possible means 41 of rescue in times of unprecedented climate change and food crises.