"Could be both," Garrus says absently, mandibles flicking in agitation. "I haven't heard of any of them. According to the Terran history I know, humanity's first contact only happened a couple of decades ago. So either we're looking at different timelines, or in the last century and a half, someone managed to bury all information on three separate incidents."

And of the two possibilities, the former seems far more likely, given the human propensity for digging into absolutely everything they're told not to.