Ryan and Emily Long are bringing an American flag cross the country to raise money for the Green Beret Foundation. They had already walked more than 18 miles by 6 p.m. tuesday evening.

"Yeah, pretty tired at this point," said Ryan. "Highway 77 went right though the middle of the Arbuckles so there's about a two mile mountain in there."

A mountain that's much harder to cross when carrying a 40 pound rucksack full of bricks.

The Longs are taking part in a national challenge. Goruck--the maker of the military-style rucksacks they're carrying--is asking volunteers to carry the rucksacks and the Flag for long distances and then pass them on to the next volunteers.

"It's going to be right at, I believe, twenty five miles when we stop give or take a little," said Ryan. "That's the plan anyways."

As they've labored on their way from Ardmore to Davis the Longs have collected donations for the Green Berets. Ryan is a former Marine who works as a firearms instructor for the United States Shooting Academy. He knows the importance of our military while Emily said Oklahomans have been generous.

"We didn't look at it, we just saw a bunch of money in the pack," said Emily. "Today some guy gave him a twenty dollar bill without even thinking about it."

The Longs will continue making their way down this winding road tonight -- Flag in hand -- for a worthy cause.