Dan Little is 76 years old and is completing the final leg of seven marathons in seven days. And when he finishes, he'll make history. 

When it’s over, the accomplished attorney and grandfather will have run just over 183 miles. His closet friends, including attorney Robert Flagler, have been tracking his every move.

“This has been a stressful week for me. I’ve gone home, and I’ll go to bed, and I’ll worry about what he’s eating and how he’s doing,” said Flagler.

For the past seven days, Little has been pounding the pavement, impressing fellow runner and friend Deana Nelson. 

“I can’t understand jumping on a plane and having to land, and get to the next hotel, prep for the next race on little sleep, race and repeat the process again,” said Nelson.

Little is defying all odds, proving that age is only number.

“He will go in the record book as the oldest man ever finish the 7-7-7,” said Flagler.

This marathon, not for the faint of heart, has taken Little to the glaciers of Antarctica.

“Toward the end of the event, it was like minus ten degrees with a wind chill that would numb your face,” said Flagler.

“I have been fortunate enough to finish an iron run, and I do not want any part of the 7-7-7,” said Nelson. 

Little has been to Cape Town, South Africa, to the Outback’s of Australia, the city of gold Dubai, Madrid and Chile. And now, Miami.

“I am so proud of Dan. I can't say how proud I am. He’s one of us, an Okie, a runner, and he’s pulling off a phenomenal event here,” said Flagler.

But the journey hasn't been easy. It’s slowly taking its toll.

“He pointed out that all of them are really starting to experience pain and stress, and rips and tears in knees and joints,” said Flagler.

But despite the aches and pains, Little's friends say he'll complete the journey, inspiring others to persevere.