The Natumpukan Half Tunnel is located in Atok in Benguet Province. It was built in the early 1950’s after the road eroded due to soil erosion. Having no other alternative route, about 50 meters of the the highway had to be reconstructed and carved from the face of the rock mountain. It has remained to this time an engineering feat of the people maintaining it. It is popularly known as “Half Tunnel” Natumpukan Half Tunnel is located 42 kilometers from La Trinidad, and 46 kilometers (29 miles) from Baguio City.