The local creation myths in many parts of the world described flora and fauna that were endemic to that location. However, as Neolithic communities expanded into city-states and then into empires that spread over ever-increasing areas, people began to encounter exotic forms of life. Further, trade routes by land and by sea brought back stories of horrifying creatures, such as krakens, sea serpents, dragons, and many other horrific forms. Some of these had a basis in reality, while some were pure fantasy. Many of these were actually transported across great distances for curiosity and for war. Thus, African ostriches were brought to the menageries of Rome, and elephants, native to Asia and Africa, became weapons of war for Alexander the Great and later the Roman legions in Europe. Horses brought to North America in the sixteenth century by Spaniards became part of the culture for many Native American societies in the eighteenth and nineteenth centuries. This had the net effect of expanding the understanding that biodiversity far exceeded the experiences of many peoples. Later, explorers brought with them natural historians who documented and categorized the many different types of microbes, plants, and animals.