MANHATTAN - There are celebrations around the world today marking the death of Osama bin Laden, but perhaps the most emotional one is happening at Ground Zero.

Since President Barack Obama announced the death last night, crowds have been gathering at the World Trade Center site where bin Laden is blamed for sending two planes into the Twin Towers on Sept. 11, 2001.

The mood at Ground Zero has been that of celebration, with cheering and singing. Others are taking time to reflect with sadness over the nearly 3,000 people who perished there.

Many friends and families who lost loved ones on Sept. 11 say the death has given them closure. Lee Lelpi, of Great Neck, lost his son, who was working as a city firefighter at the time. He says he cried when he heard the news.

Stefan Sordy, of Selden, returned to work on the Freedom Tower this morning. He says was hoping that bin Laden would be apprehended alive and taken to trial.

VIDEO: Crowds at Ground Zero, White House react to bin Laden deathVIDEO: President Obama announces Osama bin Laden's deathText of President Barack Obama's announcement