More than 100 people swam across the Great South Bay Thursday morning as part of a memorial event raising money for some important causes.

The annual Cross Bay Swim is dedicated to Maggie Fischer, a teen who was killed in a tragic crash in 1999, just days before she was due to be part of the swim. The race travels about six miles from the Fire Island Lighthouse to Brightwaters.

The fourth-generation Fire Island resident was a senior at St. Anthony's High School at the time of her death, where family members say she was one of her class' top students, as well as an accomplished athlete and musician.

Fischer's family has organized the swim for 20 years to keep her memory alive. The event itself dates back to 1927.

Maggie's dad, Bob Fischer, says dozens of swimmers involved in the event knew Maggie, but everyone has their own story. He says one person who took on the open-water event was here after his father passed just the day before. He says open-water swimmers are "a different breed."

"A lot of people in the swim remember her and were her coach, her boss or schoolmates, and she's a driving force behind much of this," Bob Fischer says.

The swim benefits Hospice Children and Family Bereavement Services and the Maggie Fischer Scholarship at St. Anthony's. Last year, swimmers and their supporters raised about $110,000.

"Fire Island was a part of her very soul," the swim's dedication page says. "Maggie was the type of person who was described by friends as being 'extremely generous and kind-hearted.' Maggie loved just having fun and the swim is dedicated to that memory of her; the memory of the way she fully lived her life and of all the amazing things she accomplished in her seventeen years."

Christopher Arena, from Amityville, was the winner.

"The swim is great, winning is great, but it's really about everybody and what we're raising money for, and who it's made in honor of," Arena says.

Mary McKenna was the first woman to cross the finish line. This was her third swim, and she says it's a Long Island tradition.

"This swim will go on for many, many years to come and that's a great thing for us to see," McKenna says.