One thing which occurs to me is the importance of hidden inventions: the sort of things which are important but haven't gotten attention, things like:
- the invention of eyeglasses
- the improvement of lighting--when did the whaling industry develop, was it to provide whale oil to light the lamps of the UK and US?
- the development of quarantine as a means to counter infectious diseases
- the accumulation of people--the greater density of population leading to more interchange of ideas
- the spread of literacy meaning easier communication of ideas among people and over time.