"Come to the park!"
It IS confusing, because in one case, the word is the same as in English, and in the other, it's only ALMOST the same.
With bank, the Turkish nominative is "banka." So when you add the -(y)A, you get "bankaya."
With park, though, the Turkish nominative is just "park." So you just add an -A (you don't need the "y," this time, because "park" ends in a consonant), and you get "parka."