ROME, Sept. 24 (Xinhua) -- U.S. fast food giant McDonald's has had a long and difficult relationship with the Italian capital.

The opening of the first McDonald's restaurant in Rome, back in 1986, sparked widespread protests. That eatery, near the Spanish Steps in the city's historical center, eventually opened.

But the protests that surrounded it morphed into the Slow Food Movement, an Italian advocacy group that promotes traditional cuisine and opposes the spread of fast food outlets of all kinds.

More recently, a plan to build a sprawling McDonald's outlet near the third-century Baths of Caracalla, ancient ruins close to the Coliseum, Circus Maximus, and the Imperial Roman Forum was blocked in July after protests convinced political leaders to change mind.

And this month, a plan to open a new branch of McDonald's near the Pantheon -- a former pagan temple first opened in the year 126 and now one of the city's top tourist attractions -- is coming under fire from critics.

"Personally, I am not a fan of McDonald's but nobody is saying they should not exist," Paolo Venezia, head of Slow Food in Rome, told Xinhua. He noted that there are 600 McDonald's franchisees operating in Italy, most of them without any problems.

"I see no problem with a McDonald's operating off highways or in airport terminals and on the periphery of towns," he said.

"But we cannot allow these kinds of places to debase our Italian cultural heritage. That is what it means when a location opens near the Baths of Caracalla or the Pantheon. We cannot look at the historical center of Rome the same way we look at an airport terminal."

McDonald's had previously operated a franchise near the Pantheon, but it closed a decade ago.

With the latest plan, the company sought to transfer the license from the previous outlet to a new one. It was blocked based on fears that it would emit levels of pollution that could damage historical structures in the area.

Barbara Cortese, head of the Juridical Observatory on the Protection of Cultural Heritage at Roma Tre University, agreed.

She said the aesthetic values of the city's historical center should be protected. But she also said the city should have a predictable and comprehensive policy that would have predictable outcomes.

"The rules should not differentiate between different franchises that have a similar footprint and it's important that none of them should go against the natural code and aesthetic of these historical areas," she said in an interview.