Biking down Nostrand Avenue on Monday, we couldn’t help but notice the police surveillance tower that had been set up at the corner of Lexington Avenue. A tweet from @FreshDotDaily yesterday reminded us that we’d snapped a photo. (The official name for the tower is Sky Watch. It was set up in Dumbo last year.) Anyone know when this was set up or why? Was there a particular incident recently that might have caused NYPD to take it up a notch on this corner?