The light bulb.
Define invention, they can be very simple or very complex. We evolved from apes and even apes are able to use tools.
i would guess a spear, or a precursor to a knife.
Wine or booze they had to get drunk
Who actually cold know that, The first greatest invention was most likely the wheel, or maybe the arrowhead, who knows?
Easy … logically, the first invention ever was - shelter.