It was touching, formal and a first for them both: President Barack Obama and former President George Bush, side by side, at site of the former World Trade Center towers. 

Last spring, just days after Osama bin Laden was killed by U.S. army, Obama flew to New York City for a few moments at Ground Zero, to respect those who had fallen in the terrorist attacks. 

But when he completed an invitation to former President George W. Bush, the invite was declined. 

On Sunday, the two stood gently in front of the bronze parapets that envelop the giant reflecting pools, which stand in the correct footprints of the former twin towers. 

First Lady Michele Obama stands by the president's side, and Laura Bush stand next to the former president. 

On May 5, when he visited the site, Obama renowned, "It did not matter who was in charge, we were going to make sure that the perpetrators of that terrible act that they established justice." 

At the time, the former president wished to stay out of the spotlight, CNN reported a Bush spokesman saying. 

But today's ceremony combined the two families, and was noticeable by the memorable sign when Michele Obama comforted Laura Bush as she broke down in tears.