A great difficulty in trying to understand vast constructions that show no interest in us:
The notion that we must be interesting.
I accept that, though we're usually avoided, probably for moral reasons, sometimes this earth has been visited by explorers. I think that the notion that there have been extra-mundane visitors to China, within what we call the historic period, will be only ordinarily absurd, when we come to that datum.
I accept that some of the other worlds are of conditions very similar to our own. I think of others that are very different—so that visitors from them could not live here—without artificial adaptations.
How some of them could breathe our attenuated air, if they came from a gelatinous atmosphere--
The masks that have been found in ancient deposits.
Most of them are of stone, and are said to have been ceremonial regalia of savages--
But the mask that was found in Sullivan County, Missouri, in 1879 (American Antiquarian, 3-336).
It is made of iron and silver.
There is nothing original in the ancient astronaut theory as presented by its modern proponent, only reworkings of outdated old theories that few believed the first time around.