Ngang Pass
Historical French texts refer to the pass as Porte d'Annam.
History
It marked the former boundary of Champa and Dai Viet until 1069, when Vietnamese [Lý dynasty]] annexed Quảng Bình into her territory.
Controlling the strategic pass was a priority through the ages as the narrow neck of land could be choked off. At the summit of Ngang Pass remains the Hoành Sơn Quan (Transverse Mountain Gate), a masonry gateway built by Vietnam's last dynasty, the Nguyễn to regulate the foot traffic across the mountain.
The scenic pass is also well known in Vietnamese literature, its beauty having been sung by many writers, perhaps the most well-known is the poem by Bà Huyện Thanh Quan.
20th century
The pass was once a major hindrance to land transportation with its winding and steep grade. A modern tunnel has since bypassed the climb, shortening the driving time through the pass as well as making it safer for drivers. The serpentine road ascending the pass is now used by sightseers only.