Where is the "Loulan" in Wang Changling's poem "Yellow sand wears golden armor in hundreds of battles, but Loulan will not be returned until it is broken"?

is located in the northwest of lop Nur, Xinjiang. It was named after the Chinese documents unearthed in the site called the city "Kuluo Laina" with the antithesis of "Loulan" and "Lu Lu Wen". At the beginning of the 2th century, the British Stein and others came here many times to steal and dig. After 195s, China scholars made investigations and excavations.

statement 1: loulan disappeared in the war. After the 5th century A.D., the kingdom of Loulan began to weaken, the northern powers invaded, Loulan city was broken, and then abandoned.

statement 2: Loulan declined due to drought, water shortage and ecological deterioration, and people had to leave Loulan because the upstream river was cut off and diverted. Loulan has promulgated the world's earliest environmental protection law discovered so far.

statement 3: the disappearance of loulan is related to the north-south migration of lop Nur. Sven Hedin believes that the period of the north-south migration of Lop Nur is about 15 years. More than 3 years ago, a European ethnic tribe lived in Loulan area, and Loulan once again entered a prosperous era more than 15 years ago, which was directly related to the wandering of Lop Nur.

statement 4: the disappearance of loulan is related to the opening of the north road of the silk road. After the opening of the Silk Road North Road through Hami (Yiwu) and Turpan, the ancient Silk Road desert road through Loulan was abandoned, and Loulan lost its former glory.

statement 5: loulan was destroyed by plague. A plague from other places claimed the lives of nine out of ten residents in Loulan city, and those who survived by luck fled Loulan one after another to avoid other places.

statement 6: loulan was defeated by biological invasion. An insect introduced from the two river basins has no natural enemies in Loulan, lives in the soil, can live on the white paste soil in Loulan area, and enters residential houses in droves. People can't destroy them and have to abandon the city. In March, 19, Sven Hedin, a Swedish explorer, went eastward along the Tarim River and reached the lower reaches of the Peacock River, looking for Lop Nur, which was uncertain. On March 27th, the expedition arrived at a mound. At this time, something bad happened, and Sven Hedin found that the water they brought leaked a lot. In the arid desert, no water equals death. They went to look for water, and an incredible scene happened. An ancient city appeared in front of them: there were walls, streets, houses and even beacon towers.