While I do enjoy modern tools such as the internet, cell phones and solar panels, I am always amazed at what man has been able to accomplish using only the simplest of tools. On a trip to Jordan I was fascinated with the complex plumbing systems used to bring water into the old market places, power the fountains, and drain water from the city streets; all this done with out electricity, pvc pipe or plumbers glue. And those systems still exist for us to observe and learn from today - over 2000 years later!
I am reminded of the quote "Those who do not learn from history are doomed to repeat it". In this case I believe that we could be, not doomed, but privileged, to repeat the lessons of the past through preservation and replication of the amazing - and simplistic - methods used by our ancestors to harness the benefits of sun, water, and wind.