Elizabeth Simon likes a challenge.

When the 39-year-old mother of four began running, she mastered longer and longer races. Looking for the ultimate run, she ran a marathon — 26.2 miles. But it still wasn’t enough. That’s when she joined the 50 States Marathon Club, aiming to finish a marathon in each of the 50 states.

She achieved her goal on Sunday when she finished her 50th marathon in Chattanooga, Tenn., crossing the finish line with her children and husband running alongside her.

Simon took up running in high school to lose weight, running two miles a day with a friend. But the exercise didn’t become a passion until 2005 when a friend asked her to help him train for a 5K — that’s 3.1 miles in length.

“I kind of got addicted to the race atmosphere,” said Simon, a Cox Communications employee. Cox Communications is the cable and broadband internet subsidiary of Cox Enterprises, which also owns The Atlanta Journal-Constitution.

From there, Simon made it a goal to run a 5K each month for a year. The following year she stepped up to run in 10K races, which are 6.2 miles long. Her first 10K was The Atlanta Journal-Constitution Peachtree Road Race.

Slowly, she worked her way up to the premiere road-racing distance: a marathon, which is 26.2 miles. Her first was the Publix Marathon, formerly the ING Georgia Marathon, in Midtown in March 2008.

The run left Simon physically sick but had her searching for a new challenge. After her recovery, she immediately began looking for more marathons.

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That’s when she came across the Houston-based 50 States Marathon Club and decided to join. Through the group, Simon has run marathons in Alaska, where she spotted a bear shortly after finishing, and Hawaii, where there was a false missile alert last year.

“For five minutes we thought we were going to die,” she said of Hawaii. “Then we found out someone pushed the wrong button.”

Simon has won three of the races she’s competed in. The feats and races all culminated in last weekend’s Chattanooga Marathon.

Joining her for various legs on the course were Lizzie, age 13, Brianna, 10, Alan, 8, and her husband Rob. Her youngest, Peyton, 5, joined in at the end so the entire family finished together.

“It was a lot of strife along the way because they had to train,” Simon said. But for her, it was worth it.

"I just wanted to finish my 50th state with my family."

Chattanooga certainly won’t be Simon’s last race. She has set her sights overseas now and intends to compete in the four of the major marathons: Chicago, Berlin, London and Tokyo. But she’s keeping the Peachtree Road Race on her list.

“I kind of want to go back and compete in the races I did at a slower rate,” Simon said.

In other news:

This year's T-shirt designs were conceptualized by well-known Atlantans who have significant ties to the AJC Peachtree Road Race. Emily Giffin: The author, who runs the race with her family every year, calls her design "Lucky Bib." She enlisted former design winner Tina Tait to do the artwork. Keisha Lance Bottoms: Atlanta's mayor calls her T-shirt design "One Atlanta." “It is my hope that our T-shirt design will celebrate the diversity of all Atlantans and mirror our goal of creating an inclusive and w