Stargate Atlantis: Season 2, Episode 15

2 - 15: The Tower

Sheppard, McKay, Teyla and Ronon visit an oppressed, poverty-stricken village that sacrifices half of every harvest to a mysterious Lord Protector in a great tower — a tower that looks exactly like the central spire of Atlantis. In exchange for the farmers' tribute, the Lord Protector defends them from the Wraith with amazing weaponry.