This is the 63rd most frequent Korean word.
주요
"Major" or "main."
The term "주요" modifies "관광지" to express that the attractions being referred to are the primary or most important ones.
이 도시의 주요 관광지는 매우 아름답습니다.
The main tourist attractions in this city are very beautiful.
"주요" here describes "역할" to indicate that the role is significant or central in its context.
그는 회사에서 주요 역할을 맡고 있습니다.
He is taking on a key role in the company.
In this usage, "주요" qualifies "문제" to signify the importance or priority of the issue discussed.