We design and implement a novel class of highly precise network instrumentation and apply this tool to perform the first exact packet-timing measurements of a wide-area network ever undertaken, capturing 10 Gigabit Ethernet packets in flight on optical fiber. Through principled design, we improve timing precision by two to six orders of magnitude over existing techniques. Our observations contest several common assumptions about behavior of wide-area networks and the relationship between their input and output traffic flows. Further, we identify and characterize emergent packet chains as a mechanism to explain previously observed anomalous packet loss on receiver endpoints of such networks.