The western secret gate of Hwaseong Fortress, featuring a detached wall section and the advanced watchtower pavilion known as Seonamgangnu. This lesser-known entrance offers insight into the fortress's sophisticated defensive architecture. Located in Suwon, it remains an important part of the UNESCO-listed fortification system that dates to the late 18th century. Visitors can observe the distinctive design of both the gate structure and the elevated watchtower that once monitored the western approaches.