When Victoria Seahorn brainstormed the route of the ING Georgia Marathon and Half-Marathon, she used a large map of Atlanta and an orange highlight marker and studied it on her dining-room floor.

She wondered how best to showcase and celebrate the best Atlanta has to offer.

"MLK was the first circle," she said, referring to the Martin Luther King Jr. National Historical Site. "What he stood for, that's what we all stand for. It's the essence of Atlanta."

She circled other locations, too, such as Georgia Tech, Piedmont Park, Decatur, and Virginia-Highland and told the route master, "Here, make it 26.2 [miles]."

The result was an event that many believe can become a top-flight running destination, perhaps even in the same league as the ING New York City Marathon, the world's largest marathon with more than 35,000 runners. The question is, can it?

"It certainly can become a major race," said Allan Steinfeld, retired race director of the famed New York race, which travels through that city's five boroughs en route to Central Park. "I told [Victoria] it can when I first met her. I told her you have to think, act and believe that it's a major marathon."

So far so good. The Georgia Marathon, set for its second running Sunday morning at Centennial Olympic Park, already looks the part. Last year, it became the second-largest inaugural marathon/half-marathon ever held with 13,479 finishers. This year's 15,000 spots are close to a sell-out.

But there's work to be done to take the race to the international stage. An important step is becoming affiliated with the Association of International Marathons (AIMs), according to Steinfeld, who has consulted Seahorn on holding the race. AIMs compiles a calendar of races all over the world — the Georgia Marathon is currently not listed on the organization's Web site (aimsworldrunning.org), but will be next year.

Reaching out to international runners can benefit the race's prestige and bring more visitors to Atlanta, Steinfeld said. He said about half of the New York City Marathon runners are from outside the United States. About 80 percent of this weekend's racers are from Georgia.

Steinfeld said a lot already has been established in Georgia. The New York race, which started in 1970 with 127 runners (only 50 finished), treats its participants with large spectator crowds who fill Central Park for the finish and are three-deep along the entire course.

The Georgia marathon gets high marks there, with "cheering zones" along the route, an historic route from downtown to Decatur and back, and a runner's first name is on front of each race number so that spectators can cheer them by name.

Seahorn has worked in stride with city government and leaders — moving the event's pre-race expo from the Georgia World Congress Center to the Georgia Dome because of damaged caused by the recent tornado was an example of the "city pulling together," said Seahorn.

She also has lined up sponsors with Georgia ties, such as ING, Delta, Mizuno USA and Emory University. ING, a Dutch financial-services company with a large office in Atlanta, is the title sponsor of six road races in the United States.

"When the idea of a marathon [in Atlanta] first came to us, we were excited to get in on the ground floor of building a world-class event," said Tricia Conahan, ING America's senior vice president and head of brand marketing. "We also have an active employee base and a commitment to community involvement here in Atlanta, so it made perfect sense for us to align with a premier running event in this area."

Seahorn expects expansion in the future, especially in hosting more international runners.

"The sky's the limit. That's what I teach my daughter [Madeline, 6]," said Seahorn, who had "an epiphany" to push for a spring race after running friend Lindsey Gabe died of breast cancer in 2004. "Last year proved that dreams do come true and it showed the area was really ready for it. ...

"The proof is in the numbers. That shows runners look at it as a great race. We're here to stay."

A good start

The ING Georgia Marathon and Half-Marathon was the second-largest inaugural race of its kind last year. The top 10 through 2007:

Event, year City Finishers

P.F. Chang's Rock 'n Roll Arizona, 2004 Phoenix 23,456

ING Georgia, 2007 Atlanta 13,479

Nike 26.2, 2004 San Francisco 7,338

Gutenberg, 200 Mainz, Germany 4,834

Orange County, 2004 Newport Beach, Calif. 4,799

Miami Tropical, 2003 Miami 3,883

OBX, 2006 Kitty Hawk, N.C. 3,499

Subway Eugene, 2007 Eugene, Ore. 3,480

Denver, 2006 Denver 3,048

Geneva, 2005 Geneva, Switzerland 2,898

Source: ING Georgia Marathon and Half-Marathon