Severnaya Zemlya any traces of land to the north of the wide strait between the Kara Sea and the Laptev Sea that they navigated. The archipelago was not put on the map until the 1913–1915 Arctic Ocean Hydrographic Expedition of icebreakers "Taimyr" and "Vaigach". The chief organiser and first captain of the Vaygach was officer Aleksandr Vasiliyevich Kolchak of the Imperial Russian Navy. The expedition was privately financed and was launched in 1910, being led by Boris Vilkitsky on behalf of the Russian Hydrographic Service. This venture accomplished its goal of exploring the uncharted areas of the continental side of the Northern
Novaya Zemlya avalanche that blocked two glacial streams and created a lake in length. Over its history as a nuclear test site, Novaya Zemlya hosted 224 nuclear detonations with a total explosive energy equivalent to 265 megatons of TNT. For comparison, all explosives used in World War II, including the detonations of two US nuclear bombs, amounted to only two megatons. In 1988–1989, "glasnost" helped make the Novaya Zemlya testing activities public knowledge, and in 1990 Greenpeace activists staged a protest at the site. The last nuclear test explosion was in 1990 (also the last for the entire Soviet Union and Russia).