BIG MOVES Ancient DNA indicates horse-riding pastoralists called the Yamnaya made two long-distance migrations around 5,000 years ago. One trip may have shaped Europe’s ancient Corded Ware culture, while the other launched central Asia’s Afanasievo culture. Nomadic herders living on western Asia’s hilly grasslands made a couple of big moves east and west around 5,000 years ago. These were not typical, back-and-forth treks from one seasonal grazing spot to another. These people blazed new trails. A technological revolution had transformed travel for ancient herders around that time. Of course they couldn’t make online hotel reservations. Trip planners would have searched...