If so, are there other examples of the same kind of thing happening in other continents (North America, Oceania)? If it was the only time such thing happened, what were the key factors that made it possible? Thanks!
These two previous posts cover your question
http://www.reddit.com/r/AskHistorians/comments/2p78a3/ive_heard_that_cort%C3%A9s_arrived_in_america_on_the/
http://www.reddit.com/r/AskHistorians/comments/1rgsfl/is_there_any_truth_to_the_commonly_cited_fact/