I had to twist my head around in circles to understand this map. Then I finally found out that the stamp honours the discovery of the Commander Islands,
a group of islands in the Bering Sea
These are from the Landscapes of the Far East series issued in 1966.
Vitus Jonassen Bering was a Danish explorer and officer with the Russian Navy. Born in 1681, he was chosen by Peter the Great to head the first Kamchatka Expedition in 1725 to map the area and to establish whether or not Asia and America were connected by a land. He returned in 1728 to report that it was all open sea between Asia and America and immediately made preparations for a return expedition, which wouldn't take place until 1741. He found Alaska and the Aleutian Islands, but storms and ill health forced his ship to land at an uninhabited island in the Commander islands group. It was there, on what would be later named Bering Island that he and 28 of his men died. The ship - the Svyatoy Pyotr, or St Peter, shown in the first stamp - made it back to the Kamchatka Peninsula after being stranded on the island for nine months. The second stamp shows the city of Petropavlovsk (Peter and Paul) - named for the two ships under Bering's command - which Bering founded in 1740.