There is proof that Chinese came to the west coast of North America in the late 6th century, and co-mingled with the native Americans. Historical Chinese records write of boat travelers trading with the Americans in the far lands now known as Mexico, and document plants that only grow in America. Also verbal records of some Americans correlate to the Chinese records. I studied this over forty years ago, was controversial back then because Columbus was "supposed" to be the first.
Columbus was recognized as the first “Government” to reach the new world. To think he was the first anything else is ridiculous.
I saw a documentary on the History channel a couple of weeks ago that explores the Chinese connection in Sout America. In fact it expored many connections. I believe it was called “Who discovered America?” Something like that. Fascinating.