An old history teacher I new was fond of quoting the 5 S's - Silver, Sugar, Slavery, Sevilla and Syphylis - sometimes Sevilla came last - it depended on what point he was trying to make. Spain found great wealth in South and Central America and transported much of it home as silver (and gold) bullion to the great enrichment of Spain and some English privateers. Much of the mining and labouring was done by the Indios working as slaves: this led to social tensions which still persist today. The introduction of cane sugar greatly modified the European diet and led eventuallty to a lot of tooth decay! Sevilla as a port of entry had a monopoly of the silver trade and grew immensely in importance as a result. There is quite a lot of evidence to suggest that syphilis was introduced to Europe by returning Spanish sailors. You can add a sixth 'S' if you like - in a real sense the importance of Spain - its involvement in European politics as far afield as England, the Netherlands, Italy and Turkey - was principally funded by the inflow of American silver. This 'free' cash income also contributed to a stagnantion in local structures which meant that when the silver flow dried up Spain was less able to adapt than it might otherwise have been.
Pedantically - we know that the first European contact with the New World was actually by the Norse in Newfoundland long before Columbus, but apart from a few artifacts that led nowhere.
Technically, the realisation that the West Indies were nowhere near China was the first step towards a real appreciation of just how big the Earth is.