Actually, when I look at this question, I am feeling awkward since I think there are a few interesting thing = things in Korea. This is because most of Koreans = most Koreans live following social rules and ideas. For example, in my case after i finished the college entrance exam, I entered into = entered In-ha University. And, when I became a sophomore, I joined a = the military because all the Korean guys should do the job in their twenties. After finishing my military duty, I am currently trying hard to get a nice job. It is really competitive and fierce to live in Korea. Anyway, I should talk about interesting thing = things about our culture. Then, I think the mixed mood of the modern style and the traditional style is one of the interesting things in Korea. For example, when you go to Jongro-gu in Seoul, you can see that a lot of buildings are mixed with traditional architecture. That's why the most interesting thing is this mixed building style. Many of foreign friends said they want to visit here since Korea has very exotic moods and atmosphere. In conclusion, I think the mixed mood of Korea is the most interesting thing in Korea's culture.

NOTE:

Use most to refer to a quantity of an unspecific group.  We use most when we are speaking in general and do not have a specific group of people or things in mind.

EX. Most students ask questions.

Use most of the X to refer to a quantity of a specific group. Note the expression includes a phrase defining the number to a specific group.      

Ex. Most of the students in my English class ask questions.

most — specific to those who are in my English class

ENTER: 3.)Register formally as a participant or member
- enroll [N. Amer], inscribe, enrol [Brit, Cdn], recruit
 

Conjunction: that  dhat

1. Introduces a subordinate clause