100 Roubles G.I. Nevelskoy

Gennady Ivanovich Nevelskoy proved in 1849–1850 that Sakhalin was an island and that the Amur River was navigable from the sea — findings that directly enabled Russian expansion into the Amur basin and shaped the borders formalized in the 1858 Treaty of Aigun with Qing China. St. Petersburg had actually ordered him to abandon the survey; he defied those orders, claimed the territory anyway, and the Russian Geographical Society's gold medal bought him enough prestige to escape court-martial. This coin was issued as part of Russia's ongoing commemorative series honoring historical figures of geographical discovery.