Frank Gennario lost his father to bone cancer when he was 16 years old, and more than anything else, he clings tightly to memories of their days together at Yankee Stadium.

As his son neared the same age three decades later, Frank made a decision: The ballpark bond between him and young Tony would have to be memorable — "something a little different," Frank said.

Over the past 10 years, the Gennarios have meticulously followed their beloved Arizona Diamondbacks to every major league stadium, a quest they completed last weekend with a series at Atlanta's SunTrust Park. The plan was hatched prior to the 2007 season, and the 59-year-old father and 24-year-old son have now seen their favorite team at 35 ballparks, including the 30 current ones.

The expedition was fueled by Frank's passion for the game, which he's had since childhood. Growing up in Queens, New York, he played stickball on the streets, cheered tirelessly for the Mets and went to games with his dad. His first in-park memory is from 1965, as a 7-year-old at Yankee Stadium.

"I do remember my dad telling me one day," Frank recalled, "He said, 'Frankie, I want you to remember this. This is something historic. You saw Joe DiMaggio hit a home run in an Old Timers' Game.'"

"I attribute a lot of my love for the game to the fact that he loved the game," Frank said about his father. "He used to live and die baseball."

Frank grew up and landed in Phoenix, where he eagerly purchased season tickets when the Diamondbacks entered the majors in 1998. He has only missed two home games in the history of the franchise — the day Tony graduated from Arizona State, and the day his 2-year-old grandson, Broxton, died from a neurological disease. Even on that devastating day, Frank's family urged him to get to the ballpark, but "there wasn't any way I was going to miss being with the family," he said.

Tony was 14 when Frank brought him to Denver for opening day in 2007, a trip that jumpstarted their quest. They checked off Milwaukee and Chicago's Wrigley Field later that summer.

That was the easy part. What followed was a decade of scouring over schedules when Major League Baseball released them in September, picking out opportune dates. Their biggest challenge was interleague play. Games at most American League ballparks are rare for the Diamondbacks — for instance, Arizona's 2016 visit to Toronto was only the second ever for the franchise.

In these photos provided by Frank Gennario Jr., Frank Gennario Jr. and his son, Tony, pose at various ballparks. Frank Gennario lost his father to bone cancer when he was 16, and he clings tightly to memories of their days at Yankee Stadium. When Frank's only son was nearing the same age, it became critical to him that they build those same ballpark memories. So the pair set a goal: see their beloved Arizona Diamondbacks play in every big league park. Ten years later, they have completed their quest. (Frank Gennario Jr. via AP)
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"Every year, the schedule would come out, and we'd sit down and say, 'This is probably what we're going to do,'" Tony said. "Ten minutes after the schedule came out, we had a tentative idea of what our trip was going to be."

Frank used airline miles and hotel points to stretch his salary as a salesman at Qwest Communications, and he had plenty of vacation days to make it work. Their mission got a boost when Tony became a bat boy for Arizona home games in 2012, giving them an in for free tickets on the road. They knocked 17 cities off their list during his bat boy tenure from 2012-16.

Plus, Frank got to see his son hanging around in the Diamondbacks dugout during games.

"That was just surreal," Frank said.

Their most memorable game is one they missed. In 2010, they skipped the first night of a series at Tampa Bay in favor of an Orlando amusement park. They were finishing up their day when Frank got a text from his wife, Ann Marie: Diamondbacks starter Edwin Jackson was through seven hitless innings.

Frank and Tony watched on television at a Bubba Gump Shrimp Co., as Jackson finished the no-hitter. Tony's phone blew up with text messages, and he had to tell his friends that no, they weren't at the game.

"We were on a roller coaster," he replied.

Frank's connection to the game has become a career for Tony, who is now the visiting clubhouse manager for the Double-A Montgomery Biscuits. Frank isn't lacking for ballpark companions, though — his granddaughters are regularly with him at Chase Field, keeping score and cheering on Paul Goldschmidt. Since the Diamondbacks arrived, Frank has fastidiously catalogued every game, keeping scorecards and notes of who joined him at the park.

"When I think about the day that I pass, they're going to say, 'Well what was your legacy? What have you left behind?'" Frank said. "It's about, 'You left the love of baseball into so many of your family members.'"

So what's next? Tony has already started following around his favorite football team, the Philadelphia Eagles, although he still has more than 20 stadiums to go.

"That's going to be a 30-year process," he said.

Frank, meanwhile, is thinking about starting all over. His 10-year-old grandson, Brody, tagged along for the recent series in Atlanta — his first Diamondbacks road trip.

"Maybe it's time the tradition continues to the next generation," Frank said. "We'll see what the schedule looks like next year."