Large-scale leaks have caused routing problems on the Internet in the past. On Dec 24, 2004, AS9121 announced over 100K routes to their peers, resulting in widely propagated invalid routes. Many large networks carried over 25K bad paths during the event, and some as many as 100K. Using BGP updates from approximately 80 peering sessions during the event, we analyze the event including the worst-hit networks, and the networks that spread the most bad paths. We find that network distance from AS9121 and maximum prefix settings on BGP sessions were not enough to prevent networks from carrying the bad prefixes. Finally, we review operational lessons learned (from feedback from involved networks) and make suggestions on future mitigation strategies.