In my opinion, electricity
The American dream.
The greatest invention ever built by mankind was probably the electric wire system that allowed us to invent further technology like computers.
Its sliced bread apparently.
The wheel is the greatest invention ever with out it we would have never had wars and some people wouldn't have died and you might not be born.
Many would say yes indeed. :)
Everything apple
The wheel.
The greatest construction ever made is the Great Wall of China which can be seen from the cosmos.
It was certainly one important invention, but not the only one.
Iphone 5
electricity
the wheel.