It's impossible to rule out all possibility of one-of human semi-circumnavigation in pre-history, either through boatmaking or unique natural circumstances. H.

It's impossible to rule out all possibility of one-of human semi-circumnavigation in pre-history, either through boatmaking or unique natural circumstances. H. sapiens neanderthalensis may have even beat us h. sapiens sapiens to water transportation. Mass migration, OTOH, needs motivating factors such as curiosity, opportunity, or existential threat, and is more difficult to navigate the young, old, infirm, and the naïve through dangerous travels.