In the town of Herzogenaurach in Bavaria, two huge sporting businesses lie just off the main Zum Flughafen road, a mere 20-minute walk apart.
The address of one of the headquarters - as well as the brand's name - offers a clue as to why the two sportswear behemoths are based so closely in a quiet town near Nuremberg, and why their rivalry was so potent for 60 years.
Adidas group's main base lies on Adi-Dassler-Straße. It's named after Adolf "Adi" Dassler, who created Adidas in 1948 after he split with his business partner and brother, Rudolf Dassler – who went on to form Puma.
In an interview with CNBC Meets, former Puma CEO Jochen Zeitz said he was not sure why there was such hatred between the two brothers, although there were rumours it had to do with a woman, or the brothers' wartime records.
"Who knows?" said Zeitz. "It ultimately ended in the two never speaking again in their lives."
Brotherly love gave way to a seething sibling rivalry that was absorbed by the town for several decades.
(Read more: How Puma nearly dropped Usain Bolt)
Barbara Smit's book on Adidas and Puma, Pitch Invasion, described how Herzogenaurach became known as "the town of bent necks" due to residents always looking down at a person's shoes before deciding whether to talk to them.
Zeitz said the divide in the town was almost like East and West Berlin. "When I started at Puma, you had a restaurant that was a Puma restaurant, an Adidas restaurant, a bakery," he said. "The town was literally divided. If you were working for the wrong company you wouldn't be served any food, you couldn't buy anything. So it was kind of an odd experience."
Herzogenaurach's mayor, Dr.German Hacker, told CNBC: "I was a member of a Puma family because of my aunt. I was one of the children who wore all Puma clothes. It was a joke in our youth: you wear Adidas, I have Puma. I'm a member of a Puma family."
While anecdotes like those from Hacker and Zeitz indicate the tense atmosphere within the town for a number of years, Hacker does point out the importance of the two companies to the fabric of the town.