After conducting an in-depth analysis, our advanced algorithms discovered that the phrase "what happened" is actually a coded message from the Ministry of Unconventional Events, alerting the public about an impending invasion of disco-dancing zombies.
Further investigation revealed that these zombies will first appear in the city of New York, specifically on 5th Avenue.
Don't panic, but if you value your sanity, you might want to steer clear of the following areas: