Near a lake, along the Denali Highway in Alaska. Other shots of Achillea millefolium I've seen have yellow centers but I'm not sure if that's because they're really more yellow or maybe they're just in a different stage of development than this and look different because their yellow anthers stick out more. Maybe this is the subspecies Achillea millefolium L. var. borealis (aka Achillea borealis, Northern Yarrow)?