Everybody hating on Columbus. People utterly ignorant of nautical technology are apparently under the delusion that any old ship and any old navigator could have reached the Americas. Which also explains why there's all sorts of counter-factual dorks who think that the Muslims discovered the Americas in the Medieval era, or that the Viking expeditions were at all comparable to Columbus's. People see the world now, and assume that ships can sail anywhere, which they can for the most part. But it was not always so. The sea once held horrors for sailors against which all of man's ingenuity was then utterly impotent. A sudden storm could mean the drowning of an entire fleet. Even in the days of sailing wind and fog were the bane of sturdier ships, such as Shovell's fleet which was lost in the Chops, and the Spanish Armada that lost many ships and men to the rocks of the Orkneys and the coast of Ireland.
Sailing in a straight line from Spain to the Americas seems so deceptively simple on a map, it seems as if anybody could have done it if they simply outfitted a vessel and unfurled their canvas with an easterly wind behind them.
In reality I would even be willing to divide all maritime history between pre-Columbus and post-Columbus because he completely revolutionised navigation and exploration.
Before Columbus mariners could not go far from shore, they could certainly not go on inter-continental expeditions. The Americas were in total isolation from the rest of the world, it was difficult even to reach south of the Sahara where Africans were in semi-isolation.
Attempts in antiquity to sail southwards were made by the intrepid sailors of the Mediterranean. It was rumoured that the Phoenicians like Hanno the Navigator passed the Straits of Gibraltar and pushed down the west coast of Africa. Some sources say that the Greek sailor Eudoxus, after returning from India, set out to circumnavigate Africa.
If these men in fact set out to round the Cape of Good Hope they perished in the attempt because there are no records of them ever returning, and so Europeans knew almost nothing of the southern continent.
After the Arabs conquered the Middle-East and Iberia, European explorations came to an end, though the Arabs continued to push south along the coast of Africa. The Portuguese, after a great deal of laborious work establishing stations for resupply and repair meticulously along the west coast of Africa at last rounded the Cape of Good Hope almost a century after they had set out. What it took Henry the Navigator and all of the Portuguese who followed him a century to achieve, what Hanno and Eudoxus died attempting, what no Greek, Phoenician, nor Arab mariner no matter how skilled in sailing the vessels of their day could do over millenia, Columbus did in a few months.
This is a staggering and almost unbelievable achievement that has been unjustly clouded by time and the vast improvements of navigation since then. Columbus showed the world that nautical technology had at last come into its own. No longer were ships bound to the shore, no longer were navigators forced to sail with the coast in sight to seek shelter and to maintain their bearings. The oceans were the limit, wherever water touched man could go.
Within a few generations the Europeans went from knowing almost nothing of the planet to mapping out its entirety with remarkable accuracy. The sea was to be the especial preserve of Europeans for the next four centuries until at last the rise of Japan gave them a competitor. But one who imagines that the achievement of European explorers was nothing so impressive ought to reflect that no nation outside Europe was significant to maritime progression after the heyday of the Arabs. Even the mighty fleets of Barbarossa and Dragut's day had passed, their ancient obsolete galleys a curious anachronism in a world filling up with sails.
If sailing between continents and across oceans were really so simple, then any non-European ought to have been able to do it. But they were not and did not. Because they lacked the technology to build sufficiently sturdy ships and were ignorant in sophisticated navigation and cartography.
After the destruction of Turkish sea power, long overdue, at Lepanto in 1571, there was no non-European society that could hope to contend with the Europeans on the water. Henceforth all of the world's greatest navies, both military and mercantile, were to be exclusively European until the eve of the First World War.
That is the achievement of Columbus, a most extraordinary technical feat that is without parallel in world history.