the expedition, with Nathu La becoming the main communication channel. In 1936-37, a diplomatic British delegation to Lhasa including B. J. Gould and F. S. Chapman used the Nathu La pass. Chapman writes that during their journey from Gangtok to Nathu la, just at the foot of the pass, was a road leading to the right and a signbord indicating Kupup. This route would have put them onto the Kalimpong-Lhasa route via Jelep La. Chapman writes that "From Gangtok the mule-track starts for the Natu La, and from Kalimpong the longer and more difficult road leaves for the Jelep La. By these two passes the road from Lhasa crosses the main range of the Himalaya on its way to India..." Chapman goes on to write that from the summit of the pass, if it were not for the mist, the delegation would have been able to see Chomolhari. At the summit, Chapman writes of groups of stones and prayer flags— these were not only for the protection of travelers, but they marked the boundary between Sikkim and Tibet. The road near the pass was paved with stones. The first stop after the pass was Champithang, a resting place for the British on the way to Lhasa. In 1938–1939 Ernst Schäfer led a German expedition to Tibet legally via Nathu La on the orders of Heinrich Himmler. This expedition also came across no gates or barriers at the pass, the border; only a ladze, prayer flags and a cairn. Post founding of PRC and independent India In 1949, when the Tibetan government expelled the Chinese living there, most of the displaced Chinese returned home through the Nathu La–Sikkim–Kolkata route. The Kingdom of Sikkim had flourishing trade during the 1950s. Calcutta was linked with Lhasa via Chumbi Valley, with Nathu La being one of the main routes for passage. The majority of trade between China and India during those years was via this route. Some traders from India even set up their shop in Yadong. Goods exported to China included medicines, fuel, and disassembled cars. India imported wool and silk. Mules and horses would be the main transit vehicle during those years. Construction to make the Gangtok–Nathu La road motorable started in 1954. It was completed and formally opened in the presence of the Maharaja of Sikkim by Jawaharlal Nehru on 17 September 1958. At the time the motorable road ended at