It's the Fourth of July weekend, and because holidays require ever-more-constant vigilance, NYPD Commissioner Bill Bratton has assured the public that a sizable beefing-up of law enforcement is happening all across the five boroughs.

"We're expecting a very safe July 4. We’ve put out extra layers of security in light of the recent terrorism events around the world,” Bratton said during John Catsimatidis's AM 970 radio show Sunday morning, referencing events that have left dozens dead in Istanbul, Bangladesh, and, most recently, Baghdad.

“It’s a shared responsibility in this time of concern and awareness about terrorism to stay aware, to, if you see something you think is suspicious, are aware of something that raises a concern, pick up a phone and call, let us come check it out,” Bratton continued.

Over on Twitter, the NYPD has singled out some Independence Day-specific security measures. They include scuba divers leaping into action:

And exploding watermelons:

Over a million people are expected to attend the East River fireworks tomorrow night. One man, FDNY explosives unit chief inspector Jim Lauer, has been overseeing the traditional display for almost two decades. You can read all about him in a new profile in the Daily News.

The city is expecting more than a million people to turn out to watch the fireworks over the East River, the top cop said. “We’re encouraging people to come,” he said.