Evidence of the existence of soup can be found as far back as about 20,000 BC. Boiling was not a common cooking technique until the invention of waterproof containers (which probably came in the form of clay vessels). Animal hides and watertight baskets of bark or reeds were used before this. To boil the water hot rocks were used. This method was also used to cook acorns and other plants.
The word soup comes from French soupe ("soup", "broth"), which comes through Vulgar Latin suppa ("bread soaked in broth") from a Germanic source, from which also comes the word "sop", a piece of bread used to soak up soup or a thick stew.
My favourite is pea and ham soup PT’s favourite is duck soup. What’s your favourite?