New York (AP) – A volunteer firefighter climbed to the top of One World Trade Center in Manhattan to get down on one knee and ask his girlfriend to marry him in a surprise proposal.

Jim Busch scaled 104 flights of stairs as a part of a charity climb on Sunday honoring firefighters who died in 9/11. The New York Post reports once he got to the top, the 31-year-old proposed to his 22-year-old girlfriend Lydia Mazza _ who did the climb with him and was unaware of his plans.

Mazza says she thought Busch was nervous about the climb, and was completely surprised.

The Stephen Siller Tunnel to Towers Foundation, which supports the loved ones of fallen first responders, organized the charity climb to honor 9/11 firefighter Capt. Billy Burke.