Nestled deep within the Huong Dien Hydropower Reservoir area in Khe Trai (Huong Tra Ward, Hue City), the Tri-Thien-Hue Regional Party Committee’s tunnel complex was the headquarters of the Regional Party Committee and Hue City Party Committee. From this underground base, they directed all activities of the liberation forces before and after the 1968 Spring offensive. Today, the site stands as a striking historical relic amid a picturesque landscape of mountains, rivers, and sky.