Extract 5 Artifacts from the territory of another major civilization.
Unstated requirement: you must extract all five artifacts on the same turn and from the same ciivilization.
This can be tricky. Play a low difficult setting and Huge map with the maximum number of City-States (41), and 4-5 AI opponents to ensure enough Artifact Sites spawn. You want at least one opponent that will grow sufficiently to influence the necessary number of sites. I like Egypt for this.
After discovering Archeology, position your Archeologists on the sites with a military unit covering them if you can. You'll probably be later in the game before you've covered all the sites and can trigger the digging. Digging times may be influenced by terrain type, so use Military Overview to check how many turns to completion. Cancel the quicker ones until the slower ones have a chance to catch up. Once they're all down to 1 turn remaining, restart all of them digging. Voila.