Hyodoncheon is a stream that flows down from Hallasan and runs through a protected natural area spanning the entrance to Soesokkak in Seogwipo and Jeju Olle Course 6. The lower stretch of the stream meets the sea at Soesokkak, while the Harye-ri side is lined with a stand of Castanopsis cuspidata. Contacting the Harye-ri office allows visitors to take part in eco-tourism programs, and the scenery changes noticeably before and after rain. Traffic in the surrounding area tends to be congested.