How was corn brought to America?

In the Old World, corn refers to wheat and this grassy cereal was not kown in many countries before the dawn of history. In the Near World, corn is that tall cereal topped with silken tassles and thick ears of golden kernels. We also call it maize or Indian corn.
Wheat, the corn of the Old World, was brought to the Americas by the Spanish settlers. Maize or Indian corn, had been grown in America for thousands of years when the Spanish arrived. Its history is one of the most fascinating tales of agriculture and modern experts are still trying to figure out many of the details.
Rice and barley, oats and wheat were developed from wild grasses by our remote ancestors. Year by year, the best seeds were selected and sown. The best strains inherited and handed on good qualities and the cultivated cereals improved through the generations. With generations of patient farming, these cereals differed greatly from their wild ancestors,
But we can recognize the wild grasses from which they were developed. Our corn too was cultivated by patient selection, But it is so far advanced beyond its wild ancestors that it no longer resembles them. Botanists have searched hard to find the ancestors of our golden corn, but so far, no one has found a single plant on earth which resembles it.
However, we do know where this wonderful cereal was first cultivated. It was grown on the slopes of the Andes of South America by the ancestors of the lordly Incas. Archeologists have found ears of many varieties of corn in tombs dating back 5,000 years. The cereal was, even then, fully developed as we know it today,
The ancient Andeans who gavw corn to the world were, without: doubt, the greatest farmers of history. Their farm tools were hoes, their only draft animal was the llama and the plow was unknown to them. Yet, before the dawn of modern history, they had developed potatoes in twenty varieties, peanuts and papaya, cashews and chocolate, tomatoes and peppers, avocados and pineapples, strawberries and mulberries, squash and tapioca and a vast assortment of beans. All these foods; were given to the world by the ancient Andeans.
The followers of Columbus lost no time in exchanging food crops and other plants between the Old World and the New. Today, corn is grown in countless countries where the summer months are hot enough and wet enough. There are, of course, countless different food crops throughout the world   but more than half of them, like corn, came originally from the terraced farms which were cultivated on the slopes of the Andes.