Pecan nuts grow on tall deciduous trees called pecan trees. Their natural region of origin is North America, where according to folk tales they were an important food for Indians. They were called pecan, meaning a nut too hard to crush with the hand. The nuts themselves, however, are remarkably delicate in flavor and aromatic. Although they resemble walnuts somewhat, they are sweeter than them. They came to Europe only in the 16th century, from where they were gradually transferred also to Africa, Asia, Australia. Pecan nuts are considered one of the tastiest nuts, with many nutritional qualities, which is why they were part of the diet of the first American astronauts.