Pretty Little Liars‘ season 2 finale “Unmasked” generated the most social media buzz of any regularly scheduled series in TV history.

The initial showing became one of Twitter’s biggest hours ever, according to SocialGuide. Fans sent a whopping 645,000 tweets during the first broadcast, hitting the 32,000 tweets per minute mark. Over the course of the day (a catch-up marathon was playing), 1.6 million tweets were sent by 667,000 users.

Some 50 topics — including five worldwide trends: Ezra, Garrett and Melissa, Spencer, Mona or Jenna, and Black Swan — trended on Twitter Monday.