4 episodes match Civilization

T'Pol finds unusual neutrino readings on a planet with a preindustrial society.

Under orders to consider any Iraqi carrying a weapon hostile, Bravo busts north towards Nasiriyah. Chomping at the bit while others are carrying the fight, the platoon finally gets 'lit up' in a violent but successful skirmish in Al Gharraf (IMDb).

The Smutnys receive unexpected guests, Josto and Gaetano reunite, Loy challenges the status quo and Oraetta is caught. (imdb)

Graham heads to America, to investigate its mysterious ancient mounds that show a sophisticated knowledge of astronomy. Does the ancient "Serpent Mound" in Ohio suggest a date for the Ancient Apocalypse - and what caused it? (imdb.com)