Great Northern Expedition

The Great Northern Expedition (Russian: Великая Северная экспедиция) or Second Kamchatka Expedition (Russian: Вторая Камчатская экспедиция) was a major Russian Arctic expedition between roughly 1733 and 1743, which mapped most of the Arctic coast of Siberia and much of the Arctic coast of North America, greatly reducing "white areas" on maps. It was conceived by Russian emperor Peter the Great, and took place under empresses Anna and Elizabeth.

Source: Wikipedia — Great Northern Expedition (CC BY-SA 4.0)