The rise of Subway: the triumphant and turbulent last decades of the world's largest fast-food chain

• Subway opened in the 1960s and scaled to become one of the largest fast-food chains in the world.
• The chain took a turn in 2015 when sales declined and after a scandal tied to pitchman Jared Fogle. 
• Despite closing thousands of sub shops, Subway was able to sell itself this week to Roark Capital. 

In the past few years, Subway restaurants have been dealing with growing pains, declining sales, and a public-relations issue with legal troubles for Jared Fogle, its former spokesman. The sandwich company has been closing hundreds of stores all over the US for the past few years and fighting allegations that its tuna isn't tuna.