This evening I watched a most interesting video on Amazon Prime.
The Enigma of the Celtic Tomb (ARTE France, 2017).
Not exactly astronomy, but interesting none the less.
Video synopsis
Archeological study of the Lavau, Vix, and Hochdorf sites in Central France along the Seine River and in Germany along the Danube River, 800 BCE, a region of early Celtic cities according to Greek historian Herodotus, 600 BCE. It seems their economy was based upon exchanging prestige gifts with the Greeks and other Mediterranean explorers for access to trade and materials. The people left no writing or money system. The video's premise is these Celtic towns marked the transition from Greek culture to the Roman World of War.