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Other than being one of the two or three greatest navigators in history. Before the invention of the sextant—which meant navigating just by the sun and estimating his ship's speed by eye—he sailed across the notoriously stormy North Atlantic without losing his way, and keeping his crew in line with prayer and discipline.
Everyone thought Asia would be the next land mass. Hah! But there was no Wikipedia or Google earth then, sorry. He had his latitude about right for Japan, but of course it wasn't Japan. He landed in the Bahamas on an island the natives named after a lizard—Guanahani—which we now call the iguana. But Columbus had bigger plans and a slightly greater vision. He called it San Salvador or "Holy Savior." He explored the area and sailed back to Spain.
Then he returned to that same spot (4000 miles each way) to explore some more—three times. Safely, without getting lost. How are you on a lake in a rowboat, in a cloudy downpour? Then we can talk about "idiot."
The Aztec, while the greatest civilization on the continent before Columbus was notoriously cruel and bloodthirsty.
In the 12th and 13th century, their practice of human sacrifice was limited to an occasional choice maiden or young man from their own tribe. By the 14th century, it expanded to include that demographic from other tribes to substitute for their own.
As you can imagine, the other tribes did not take kindly to this practice, so by the 15th century, it expanded to entire villages of men, women and children. Many tribes were wiped out by the Aztec, others faced near extinction. It was only the arrival of the Spaniards and the fall of the Aztec empire early in the 15th century which saved what little was left of them.