White Sea small. The main island group is the Solovetsky Islands, located almost in the middle of the sea, near the entrance to Onega Bay. Kiy Island in Onega Bay is significant due to a historic monastery. Velikiy Island, located close to the shore, is the largest island in the Kandalaksha Gulf. The White Sea is a water-filled depression in the block of a continental shelf known as the Baltic Shield. Its bottom is very uneven and contains the Kandalaksha Hollow in the northwest and the Solovetsky Islands in the south. Also, the Onega Bay has many small underwater elevations. The opening
Arkhangelsk Oblast most of these became unprofitable and have been destroyed. In the 1970s and 1980s the aviation was active, with all district centers connected to Arkhangelsk with regular flights, Kotlas being the second important hub. Currently, it has almost disappeared. There are two airports in Arkhangelsk, but regular local flights are only carried out to the destinations which do not have rail or road connections, such as Novaya Zemlya, Solovetsky Islands, the Nenets Autonomous Okrug, the Onega Peninsula, and the north of the oblast. The exceptions with functioning airports are Mezen, Leshukonskoye, and Onega. The oil transport system, Baltic Pipeline System,