K-Hiking Has Become a Popular Activity For Foreign Visitors to Seoul
|The easy access to various mountain trails is something very unique to Seoul that the government has done a better job of promoting and maintaining hiking trails. This has led to a large increase in foreigners hiking these trails:

Wearing hanbok (Korean traditional attire) and walking around Gyeongbok Palace, eating street food and shopping for K-pop merchandise and cosmetics used to top to-do lists for people traveling to Korea.
Now, a new experience is climbing in popularity — literally. Hiking Korea’s urban mountains, often dubbed “K-hiking,” has quickly become one of the most unexpected yet popular activities among international tourists.
Searching hashtags like #seoulhiking, #hikingtourism or #hikinginseoul on Instagram now turns up over 10,000 posts. No matter which mountain in downtown Seoul, it is now common to see foreign tourists exploring mountain paths or taking photos at the summits.
You can read more at the link, but K-hiking has definitely become popular with foreign tourists. I have seen way more foreigners on Korean trails today compared to 20 years ago.