In 1879–80, Russian explorer Nicholas Przewalski travelled in northern Tibet. In 1885–1887 Arthur Douglas Carey and Andrew Dalgleish travelled in northern Tibet. In 1889, Gabriel Bonvalot with Prince Henri of Orléans and Father Constant de Deken crossed the mountain range of Tibet. In 1893–94, Jules-Léon Dutreuil de Rhins with Fernand Grenard explored most inaccessible and least-known regions of northern and western Tibet. The Swedish explorer Sven Hedin conducted 1893–1897, 1905-1909 and 1927-35 three expeditions which mapped big parts of Tibet. Hedin had a doctorate in geography and was a skilled cartoonist and writer who together with other participants in these expeditions carefully documented what they saw in Tibet from many different aspects during these expeditions. Hedin and his followers made surprisingly accurate and detailed maps of large parts of Tibet compiled extensive documentation of their observations. Hedins books and lectures about his expeditions made him a world-famous person in the years before the First World War. In 1898, a Canadian missionary medical doctor, Susie Rijnhart, and her husband and baby attempted to reach Lhasa from the north. The couple came to within one hundred miles of Lhasa before being turned back. The baby died and the husband disappeared, but Dr. Rijnhart survived and made her way alone out of Tibet. British experience in Tibet (particularly the instructions by Sarat Chandra Das) was used by the first known Japanese explorer of Tibet, Zen monk Ekai Kawaguchi, who crossed into Tibet in 1899 disguised as a Chinese monk, reached Lhasa and stayed for long enough to serve the Dalai Lama as a therapist. Russian explorers reached Lhasa several months later - Gombojab Tsybikov in August 1900, and Ovshe Norzunov in February 1901, officially as Mongolian pilgrims. They had the advantage of using Nain Singh's publications, Lhasa pilgrimage experiences of their native Buryat and Kalmyk kinsmen, and support of Russian-born associate of the Dalai Lama, Agvan Dorzhiev. Tsybikov and Norzunov became the first photographers of Lhasa known by name, and the earliest published photographers of the city. For Norzunov, a Kalmyk nobleman and devout Buddhist, it was his second visit to Lhasa, but his earlier trip, taken in 1898–1899, was not supported by Russia or have exploration on agenda. At that very time, Przewalski's student Pyotr Kozlov headed to Tibet and explored the Chinese-controlled part of Kham, but was stopped at the border of Tibetan-controlled territory in October 1900 and had to retreat.