The global chain, whose best-known product is the Big Mac burger in a bun, says it will be its first vegetarian outlet.

BBC: McDonald's opens vegetarian-only restaurant

This offering relocates the innards of the Big Mac -- burger, pickle, special sauce, lettuce, cheese -- in a tortilla to create a small burger-burrito hybrid.

CNN: Fast food treat is shrinking

In Seoul, the Big Mac has to compete with Burger King's Whopper, Lotte Burger (a local rival) and South Korean alternatives.

ECONOMIST: Deflating