Where was steel invented?

The metal element of Iron (Fe) was never "invented" as it has existed across the Universe for billions of years. That being said humanity is thought to have first exploited Fe for industrial and social uses some 3500+ years ago. Since the use of Fe has become an inseparable aspect to modernity through steels and other metal working. Although Fe was never invented, it was to be discovered, exploited and refined through human technology.