Complete Mass Effect 3 twice, or once with a Mass Effect 2 import.

Make the final assault.

Finish all multiplayer maps or all N7 missions in single-player.

Extract ancient technology.

Call down an orbital strike.

Reach level 15 in multiplayer or level 50 in single-player.

Survive the swarm.

Establish or rekindle a romantic relationship.

Win a political stand-off.

Complete one multiplayer match or two N7 missions.

Defeat a Harvester.

Kill 10 guardians with headshots from the front while their shields are raised.

Learn more about the Prothean Empire.