(I'm a geography nerd like most of you here but I never found this city in quizzes alike)
Every time I take a quiz involving Chinese cities, I forget about Chengdu. Then when the quiz is over, I see the answers and think, "Ah, Chengdu!".
It's a massive city with a long history and yet. . .my brain refuses to remember it.
My apologies to the residents of Chengdu but my subconscious clearly refuses to believe you exist.
Shangri-La renamed recently to attract tourists, so it was the only one that slipped my mind.