This is the 1587th most frequent Korean word.
도쿄
Tokyo (the capital city of Japan).
Here, "도쿄" is used as a proper noun referring to a specific place — the capital city of Japan.
도쿄는 일본의 수도입니다.
Tokyo is the capital city of Japan.
In this sentence, "도쿄" is again a proper noun, but it serves as the location where the action of eating took place.
도쿄에서 맛있는 음식을 많이 먹었어요.
I ate a lot of delicious food in Tokyo.
Here, "도쿄" is used to specify the subject "the streets of Tokyo," indicating possession or association.