The ability to understand and contemplate the importance of harnessing energy is the biggest achievement. I’m not talking about the physical side either.
If I’m not allowed abstract thought and natural language I think that’s probably out too.
Personally I think it’s a pretty blinkered to hold that these development was all down to evolution* and not to human beings striving to explore their environment in exactly the same way as everything else in this thread but what the heck.
*not that I deny this, but it’s a criticism that applies equally to everything humanity has ever accomplished.