The Jan 14 Economist mentions the Zheng He map, supposedly dated 1418, showing the world with remarkable precision. If true, it would be astounding evidence that Chinese sailors went around the world long before Europeans, and vindicate many of the controversial claims by Gavin Menzies in his best-seller 1421 The Year the China Discovered the World. Turns out that radiocarbon dating confirmed the dates mentioned by Economist, but controversy remains.
I'm surprised that nobody links this with discovery of steel implements found in the Ozette community, in Western Washington. A mudslide in the early 1400's buried the village long before Europeans arrived. Where did they get the steel?