The golden age of man is a concept which has origins amongst almost all the people of the world. The universal concept is of a time when man had no need to work or till the earth, there was an abundance of food, no wars or crime such as we have to deal with today. During this mythical time man was in communion with the gods (there is no definite description of "the gods" available), and peace and harmony was everywhere.
This idylic state existed in the myths of the Egyptians, the native Americans (north and south), the various Indian peoples, the Chinese as well as European and African people. Today we regard such stories as being merely the imaginings of ancient people and that such times did not really exist. Would such myths be so universal the world over without something to spark such imagination. Findings of tropical plants beneath the ice in Antartica as well as frozen animals in Alaska and Siberia would seem to indicate that the climate in these regions was once very different to what it is in our time. Also we should consider how our oil reserves came into existence. The massive oil reserves in some of the driest parts of our planet can only have come from very abundant plant life at some time in the past which became buried during some natural catastrophe. Do these indicators perhaps add credence to the ancient myths of a golden age?
Some of the ancient myths are truly mind boggling. The Jains for instance, describe the first age of man where men were 4 miles high and lived for a time of 40 to the power of 194 years (give or take a century or 2), this is 40 followed by 194 zeros in years (4 palyopama). Why would they even need to imagine a number that big? Other cultures and religions are not specific as to how large people were, but the Christian bible describes Adam and his descendants as living for hundreds of years. Giants are also common in ancient myths (4 miles high is bit much).
I personally would be inclined to disregard the extreme stories, but we should consider that there are many reports which tend to support some of these myths. There have for instance been reports of the finding of giant skeletons, some estimated to be as tall as 20 metres. Old buildings also have doorways which are more than 10 times higher than needed for modern man, why is that ? Some old buildings are built with dressed stones which we would have great difficulty moving today, but if there were giants in the past, then such things become feasible, perhaps we can reverse engineer the size of the humans needed to build with such stones. A 1300 ton stone, which to us is impossible to build with, may have been a covenient size to people in ancient times. There are however other amazing feats of construction which cannot be explained merely by having oversized humans, the stone boxes in the serapeum in Egypt is a good example. There would not be enough space for giants to move these 100 ton boxes underground, which indicates some technology of which we know nothing about.
We should perhaps have a closer look at ancient myths, it may be that our origins are much different to what we currently believe. It is also more than likely that the ancients were well ahead of us in many fields.