World Trade Center operator Larry Silverstein says his heart is shattered every time he visits ground zero and the pulverized ruins of his marquee buildings.

Silverstein – owner of Silverstein Properties, which managed the towers as a lessee of the Port Authority – has repeatedly vowed to rebuild, but thinks four buildings of about 50 stories each would be more practical than the giant towers destroyed in last week’s terrorist attack.

“It’s difficult, from a pragmatic point of view, to now ask tenants to go up into the upper stories in 110-story towers,” he told The Post.

The real estate pooh-bah said he watched the sickening drama unfold from the safety of his Midtown home and later in his Midtown office.

He watched in horror with his face pressed to his office window.

Silverstein – like many others – was favored by fate. He had been scheduled to meet with Port Authority officials that morning in his temporary office on the 88th floor of the north tower, but the meeting was canceled.

“It’s an absolute miracle we all didn’t get caught,” Silverstein said, adding that his children, Lisa and Roger, who both work for him, are safe.

But Silverstein Properties did not go unscathed in the carnage unleashed by the kamikaze fanatics. Four members of his staff are missing – or dead, said Silverstein, who also was the lessee of Buildings 3, 4 and 7.

Those missing are John Griffin, John O’Neill, James Corrigan and Charles MaGee.

Another senior staffer, Geoff Wharton, was meeting with PA Executive Director Neil Levin at a Windows on the World breakfast, but left early to call on a prospective tenant.

Wharton survived, but Levin is still missing.

“We lost four people and it’s a miracle that we didn’t lose more, and it’s an absolute miracle that God spared some and not others,” Silverstein said.

“It’s pretty tough to understand why and how. It makes sleeping at night difficult. It’s so depressing, you have to steel yourself each day; it’s the magnitude of the event on our lives.”

But Silverstein is bullish on the Big Apple and is intent on rebuilding.

He revealed that he will start with a new WTC 7 as soon as practical.

What will rise in place of the Twin Towers will take longer to determine, he said, adding that his office has been flooded with proposals.

One thing is certain – any choice will be emotional, he said.

The only thing Silverstein is sure of is that the new WTC will include a memorial to honor the thousands who lost their lives in the terrorist attack.

He said many people have asked that grass, not buildings, cover the site, but most have urged him to rebuild as a defiant gesture to the terrorists.

But any new development will be smaller than the Twin Towers, Silverstein said, noting that four half-sized towers would be more sensible.

His partner in the retail mall at the WTC, Westfield America, wants to move forward with the redevelopment of the retail space, he said.

He noted that many decisions about the site will be made with the PA, the feds and Marriott, which had a hotel at the center. Other government agencies would also want a hand in any plans.

Silverstein shrugged off concerns about his ongoing responsibility of paying more than $115 million a year in rent to the Port Authority.

“That’s what business-interruption insurance is for,” he said.

“The devastation is an extremely difficult thing to deal with. It affects all our lives.”