Nakhchivan on 28 July 1920, and the city became part of the newly formed Nakhchivan Autonomous Soviet Socialist Republic. The Treaty of Moscow of 16 March 1921, and later the Treaty of Kars of 21 October 1921, between Soviet Union and Turkey agreed that Nakhicheva would be an autonomous territory under the protection of Azerbaijan and delimited its borders with Turkey. In February 1923, the city formed part of the Nakhchivan Autonomous Krai within the Azerbaijan Soviet Socialist Republic (ASSR), but later became the capital of the Nakhchivan Autonomous Soviet Socialist Republic within the ASSR in March 1924. When Azerbaijan declared independence from the Soviet Union, Nakhchivan remained part of the Republic of Azerbaijan. Following the 2020 Nagorno-Karabakh war, a trilateral ceasefire was signed between Armenia, Azerbaijan and Russia. According to the agreement, Azerbaijan will gain a road access to Nakhchivan through Armenia which will be secured by Russian peacekeepers. Since 9 June 2009, the Bulqan, Qaraçuq, Qaraxanbəyli, Tumbul and Haciniyyət villages of the Babek District are included in the scope of the administrative-territorial unit of the Nakhchivan city. Ecclesiastical history The bishop of Mardpetakan resided at Nakhchivan, and the Armenian historian Tovma Artsruni records Sahak Vahevuni as bishop of Nakhchivan and Mardpetakan and brother of Apusahak Vahevuni. Geography The city is spread over the foothills of Zangezur chain, on the right bank of the Nakhchivan River at an altitude of almost . The floods and soil erosion spiked because of the decreased forest cover along riverbanks. As a result, reforestation projects implemented in the city to encourage tree planting. Climate Nakhchivan has a continental semi-arid climate (Köppen BSk) with short but cold, snowy winters and long, dry, very hot summers. Population According to the State Statistics Committee of Azerbaijan, the number of population of city was 63,8 thousand in 2000. Demographics Economy Traditionally, Nakhchivan was home to trade industry, handicraft, shoemaking and hatmaking by Azerbaijanians. These industries have been largely replaced. The restoration enterprises and development industry, liberalization of foreign trade and the extension of the customs infrastructure, which has been largely responsible for Nakchivan's growth in the last two decades, are now major parts of Nakchivan's economy. Culture The city has a wide range of cultural activities, amenities and museums. Heydar Aliyev Palace, which has a permanent local painting exhibition and a theatre hall for an audience of 1000 people, and a recently restored Soviet-time Opera Theatre where