Haron Lagat crosses the finish line to win the Army Ten-Miler in 49 minutes 23 seconds. (Dillon Mullan/For The Washington Post)

In the shadow of the Pentagon, Haron Lagat began his Sunday run among thousands. In a camouflage tank top, the 34-year-old Army specialist blended in.

Ten minutes later, nine others kept pace with Lagat as he crossed the Arlington Memorial Bridge into the District. After he rounded the Kennedy Center and turned up Independence Avenue, that lead pack was down to five.

At the six-mile mark of the Army Ten-Miler, Lagat steadily strode away from the rest. Across the 14th Street bridge and down the stretch, he was comfortably alone.

Lagat crossed the finish line first in 49 minutes 23 seconds. Susan Tanui, 30, was the fastest female runner with a time of 56:50.

While he broke a sweat maintaining a sub-five minute pace on an uncharacteristically humid October morning, Lagat still had plenty of time to enjoy the sights.

Dustin Jutras (692), Hunter Jutras (693) and their team in T-shirts honoring Dillon Jutras pose following the race. (Dillon Mullan/For The Washington Post)

“That was so beautiful. I came for the scenery. I love it; D.C. is beautiful,” Lagat said. “I’m excited to stay here until Tuesday. [On Monday,] I’m going to tour the city as much as I can before I head back. I want to see the White House and all that.”

Lagat lives and trains in Fort Carson, Colo. On Oct. 1 in Minnesota’s Twin Cities, he finished fourth in 47:40 at the USA Track & Field 10 Mile Championships.

“After U.S. champs last weekend, I came here a little bit tired,” Lagat said. “I treated this race like hard training.

“But in the end, winning is the best thing for me.”

Rain began falling about 20 minutes after the first wave of runners hit the course. Nevertheless, an estimated 1,800 spectators attended the race. Three bands — one brass quartet, one from Paul VI High and a country group with electric guitars and a drum set — provided the loudest support.

“The first three miles were getting hotter and hotter. Then when it started raining, I was like, ‘This is a great feeling,’ ” said Tanui, also an Army specialist at Fort Carson. “This is a unique race. I enjoy running in this city and the people cheering and the bands. It’s not like any other race.”

Of the 35,000 registered runners, 57 percent were active duty, reserve, guard, retired military, veterans, military family dependents or Defense Department employees.

Many ran with some sort of tribute to a fallen service member. Elite runners and weekend joggers alike enjoyed the noncompetitive spirit.

“We were saying during the run how this is the best run of the year,” said Dustin Jutras, a senior on the George Mason cross-country team who ran with his younger brother, Hunter, a sophomore teammate. “It’s great how everyone is out there with purpose, trying to better themselves. It’s great for us to be in the middle of that.”

Dustin and Hunter’s older brother, Dillon, was killed in action in Iraq in 2005. On Sunday, they led a team of 15 runners wearing shirts with Dillon’s picture.

“Everyone here is running for a reason,” Hunter said. “It’s less about what time we’re running and more about why we’re running.”

Throughout the race, the brothers alternated carrying the American flag.

“After we took the last turn,” Hunter added, “I made sure to hold it up high so everyone could see.”