The earliest fully developed spoke-wheeled horse chariots are from the chariot burials of the Andronovo (Timber-Grave) sites of the Sintashta-Petrovka Proto-Indo-Iranian culture in modern Russia and Kazakhstan from around 2000 BC. This culture is at least partially derived from the earlier Yamna culture. It built heavily fortified settlements, engaged in bronze metallurgy on an industrial scale, and practiced complex burial rituals reminiscent of Hindu rituals known from the "Rigveda" and the "Avesta". Over the next few centuries, the Andronovo culture spread across the steppes from the Urals to the Tien Shan, likely corresponding to the time of early Indo-Iranian cultures.