What was the human hisory between North American Asia Eurasia and Europe before the 1450's?
Not much, since Columbus (and after him the increasing flood of explorers from Europe) didn't get to the Americas until almost 1500.
There are a couple, though, but they are so far in the past that here are controversies about them:
http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla:en-US:official&hs=Ssr&ei=E-liS4XpK4mQNo2u3KEO&sa=X&oi=spell&resnum=0&ct=result&cd=1&ved=0CAYQBSgA&q=leif+erikson&spell=1
http://archaeology.about.com/od/bcthroughbl/qt/beringia.htm