MANHATTAN (WABC) -- Today is National High Five Day. For David Hale Sylvester, who has hugged and high-fived more than half a million people, it might as well be Christmas.
"My plan was not to become the Human High Five," he says during an afternoon spent connecting with strangers - palm first - near the Freedom Tower. "It's funny where the world takes you, man."
Growing up in Philadelphia, Sylvester found the brother he always wanted in Kevin Bowers, a childhood mentor. Bowers worked as an IT engineer in the World Trade Center and tragically lost his life in the September 11th attacks.
"I decided to ride my bike across the United States to process everything," Sylvester says. "What I found was people wanted a connection. People wanted a hug. People wanted a high five. People wanted to talk."
Sylvester was hooked on hugs and high fives. He rode his bike the length of Africa, then Asia, Australia, and twice more across the U.S.
He traveled to 37 countries and all 50 states hugging, high-fiving and connecting with as many people as he could along the way.
"I thought of all the smiles I could be a part of, being a part of this kinetic thread of good deeds," he says.
Sylvester has focused on areas affected by violence: Las Vegas, Orlando, Sutherland Springs. He believes his own story, paired with a hearty slap or a deep embrace, can help those in pain.
"I can sort of let people know, hey, listen, there can be a purposeful life and a smile after tragedy."
Now, he's planning his most ambitious endeavor yet: to hug the world in 80 days, with hug and high five events planned on six continents. He plans to embark September 12th - 18 years to the day after his journey began - and that's no accident.
Before leaving Ground Zero, Sylvester finds Kevin Bowers on the 9/11 Memorial and presses his palm against the name.
"I just wanted to high five him one more time because I miss him," he says. "So I'm gonna do what I can with him in my heart to make the world a better place."