On August 17th, 2017, a gravitational wave event unlike any other showed up in one of the LIGO detectors: at Hanford, WA. Just a few days prior, the first black hole-black hole merger with all three detectors running — LIGO Livingston, LIGO Hanford, and Virgo — was detected. This time, a new event was recorded, but instead of having 1–2 seconds of data, the significance lasted over a minute. With a false alarm probability of only one-in-300 billion (3 × 10^–12), an alert went out to everyone on the team. But LIGO Livingston, which had come through every time before, showed nothing. Without a signal in all detectors, there was no “event” to declare. Without confirmation, this would merely go down as a false alarm.