But they were a maritime culture. Even today, the coast of Peru is a significant source of all of the, or a good chunk of the seafood in the world. But a significant culture developed there. These are the remnants of their pyramids. And they developed, we believe, in the fourth millennium BCE. So this is around the same time as when Egypt first got unified by Menes, or you have the first Sumerians in Mesopotamia. And as far back as them, you have these khipu knots, which many archaeologists view as a form of writing, as a form of record-keeping.