Short answers, pulled from the story.
Sintashta is a Bronze Age fortified settlement in Chelyabinsk Oblast, Russia, dating to approximately 2100-1800 BC. It is the type site of the Sintashta culture and has been characterized as a "fortified metallurgical industrial center" due to evidence of copper and bronze metallurgy found in every excavated house.
Excavations at the Sintashta burial ground uncovered chariot burials among the forty graves of the largest cemetery, known as Sintashta mogila (SM). These are considered the oldest known chariots in the world and were accompanied by horse sacrifices, weapons of stone, copper, and bronze, and ornaments of silver and gold.
Sintashta was discovered in 1968 by an expedition from the Ural State University. Research and excavations were led by V. F. Gening and G. B. Zdanovich under the Ural-Kazakhstan Archaeological Expedition until 1986, with additional contributions from L. N. Koryakova, V. I. Stefanov, and N. B. Vinogradov.
Scholars have noted that the funerary sacrifices at Sintashta, including horse burials with up to eight horses in a single grave, bear strong similarities to funerary rituals described in the Rig Veda, one of the oldest surviving religious texts.
Sintashta is located in the steppe just east of the southern Ural Mountains in Chelyabinsk Oblast, Russia, named for the adjacent Sintashta River. Its origins involved the assimilation of multiple cultures, including the Pit-grave, Catacomb, Poltavka, and northern Abashevo, making a purely Indo-Iranian attribution inaccurate.
Arkaim is located about 30 kilometers from Sintashta. Both are Bronze Age fortified steppe settlements with fortifications of unprecedented scale for the region, and both belong to the broader Sintashta culture.