World Trade Center security

One World Trade Center towers proudly over Lower Manhattan, the new focal point of New York City's skyline.

But what does it take to keep 16 acres of office space, a transit hub, a national memorial and a museum safe? It's a question for Deputy Inspector Ron Shindel, the commanding officer of the Port Authority of New York & New Jersey's police force on the site.

Shindel has a perspective on the Trade Center no one else has: He's been in command there before. He was an NYPD deputy inspector on Sept. 13, 2001, when he was called to the chief's office and given a very important mission. They called it Operation Ground Zero.

"It was the most important thing I've ever done, not necessarily the most enjoyable thing I've ever done," Shindel said recently.

For 141 days he and the men and women under his command worked to maintain the site and clean it up. They provided security, sat in on morgues and collected evidence. Shortly after the mission was complete, Shindel retired. He stayed away from policing for 11 years, but came to the Port Authority Police and was placed in charge of the George Washington Bridge. In June 2015, he was promoted and reassigned back to the Trade Center. It's a busy assignment and his eyes are on keeping the people and place safe from any terrorist's desire to bring violence back to the site of 9/11.

"This is a hard target, with trained professionals guarding it," Shindel said.

He's had great honors since he took over in June, like protecting the pope. Shindel himself measured the distance from where the pope got out on West Street to walk to the National 9/11 Museum: 306 feet to be exact. They kept the pope safe and everything went well.

Shindel is full of energy and walks to bustling World Trade Center site with a smile on his face, greeting cops and helping tourists like the police chief of a medium-sized town.

"I love it," Shindel said. "It's great to be here, and it's an honor to be here."