Human sacrifice was practiced in many human societies beginning in prehistoric times. By the Iron Age (1st millennium BCE), with the associated developments in religion (the Axial Age), human sacrifice was becoming less common throughout Africa, Europe, and Asia, and came to be looked down upon as barbaric during classical antiquity.[citation needed] In the Americas, however, human sacrifice continued to be practiced, by some, to varying degrees until the European colonization of the Americas. Today, human sacrifice has become extremely rare.