Kicking off on Jan. 11, the nine-day festival runs through Jan. 19 and invites thousands of people to brave the subzero temperatures to trek on a frozen river surrounded by volcanic canyons.

Cheorwon County, located at the tip of the country bordering North Korea, is one of the nation's coldest counties. Its Hantan River is 136 kilometers (84.5 miles) long and flows through Pyonggang, ...