The famous author Joseph Conrad, who wrote about modern imperialism, once wrote that "power is an accident arising from strength." Spain had just reconquered their homeland from the Moors and so they felt blessed by God in their quest for a trade route to the West. Columbus happened to be the man of the hour. Spain thought little of the Norse or their sagas detailing "Vinland" to the West, so they honestly thought they were the first to discover the Americas. They had no idea that the "Indians" had already discovered it when they crossed the Pacific.
What were the different routes that the original "Americans" used to cross over from Eurasia c. 10,000 BC?