Donald Trump visited a McDonald's restaurant on Sunday.Doug Mills/Pool via REUTERSDonald Trump visited a McDonald's in Pennsylvania on Sunday.It was the latest in a long tradition of presidential candidates invoking the fast-food chain.Besides being a famous place to eat, McDonald's has also been an employer to many Americans.Donald Trump's Sunday visit to a McDonald's restaurant shows that presidential candidates still view the fast-food chain as a major opportunity to appear relatable to voters.Trump is far from the first candidate to invoke the Golden Arches during their campaign.