Between 1893 and 1897, Hedin investigated the Pamir Mountains, travelling through the Tarim Basin in Xinjiang region, across the Taklamakan Desert, Lake Kara-Koshun and Lake Bosten, proceeding to study northern Tibet. He covered 26,000 kilometres (16,000 mi) on this journey and mapped 10,498 kilometres (6,523 mi) of them on 552 sheets. Approximately 3,600 kilometres (2,200 mi) led through previously uncharted areas.
He started out on this expedition on October 16, 1893, from Stockholm, traveling via Saint Petersburg and Tashkent to the Pamir Mountains. Several attempts to climb the 7,546 metres (24,757 ft) high Muztagata—called the Father of the Glaciers—in the Pamir Mountains were unsuccessful. He remained in Kashgar until April, 1895 and then left on April 10 with three local escorts from the village of Merket in order to cross the Taklamakan Desert via Tusluk to the Khotan River. Since their water supply was insufficient, seven camels died of thirst, as did two of his escorts (according to Hedin’s dramatized and probably inaccurate account). Bruno Baumann traveled on this route in April, 2000 with a camel caravan and ascertained that at least one of the escorts who, according to Hedin, had died of thirst had survived, and that it is impossible for a camel caravan traveling in springtime on this route to carry enough drinking water for both camels and travelers.[5]
According to other sources, Hedin had neglected to completely fill the drinking water containers for his caravan at the beginning of the expedition and set out for the desert with only half as much water as could actually be carried. When he noticed the mistake, it was too late to return. Obsessed by his urge to carry out his research, Hedin deserted the caravan and proceeded alone on horseback with his servant. When that escort also collapsed from thirst, Hedin left him behind as well, but managed to reach a water source at the last desperate moment. He did, however, return to his servant with water and rescued him. Nevertheless, his ruthless behavior earned him massive criticism.[6]
In January, 1896, after a stopover in Kashgar, Hedin visited the 1,500 year old abandoned cities of Dandan Oilik and Kara Dung, which are located northeast of Khotan in the Taklamakan Desert. At the beginning of March, he discovered Lake Bosten, one of the largest inland bodies of water in Central Asia. He reported that this lake is supplied by a single mighty feeder stream, the Kaidu River. He mapped Lake Kara-Koshun and returned on May 27 to Khotan. On June 29, he started out from there with his caravan across northern Tibet and China to Beijing, where he arrived on March 2, 1897. He returned to Stockholm via Mongolia and Russia.

Source: Wikipedia.