Big Diomede seen from its nearest neighbor, Little Diomede
|Area||29 km2 (11 sq mi)|
|Highest elevation||477.3168 m (1,566 ft)|
|Population||0 (permanent inhabitants)|
|Ethnic groups||Inupiat (formerly)|
Big Diomede Island ( Russian: о́стров Ратма́нова, ostrov Ratmanova (Russian for Ratmanov Island);  Inupiat: Imaqłiq) or "Tomorrow Island" (due to the International Date Line) is the western island of the two Diomede Islands in the middle of the Bering Strait. The island is a part of the Chukotsky District of the Chukotka Autonomous Okrug of Russia. The border separating Russia and the United States runs north-south between the Diomede Islands.
Big Diomede Island is located about 45 km (28 mi) southeast of
Cape Dezhnev on the
Chukchi Peninsula and is
Russia's easternmost point or, technically, the westernmost point. The coordinates are
BIG DIOMEDE ISLAND Latitude and Longitude:
. The rocky tuya-type island has an area of about 29 km2 (11 sq mi)  The International Date Line is about 1.3 km (0.81 mi)  east of the island. The highest point of the island is at 65°46'24.64" N, 169°04'06.61" W where the elevation reaches 1,566 feet.
The first European to reach the islands was the Russian explorer Semyon Dezhnyov in 1648. The Russian navigator (Danish nationality) Vitus Bering re-discovered the Diomede Islands on August 16, 1728, the day on which the Russian Orthodox Church celebrates the memory of the martyr St. Diomede. 
After World War II, the native population was forced off Big Diomede Island to the mainland in order to avoid contacts across the border. Today, unlike Alaska's neighboring Little Diomede Island, it has no permanent native population, but it is the site of a Russian weather station and a base of Border Service of the Federal Security Service of the Russian Federation troops (FSB).  
During the Cold War, the section of the border between the U.S. and the USSR separating Big and Little Diomede became known as the " Ice Curtain". In August 1987, however, Lynne Cox, an American long distance swimmer, swam from Little Diomede to Big Diomede (approx. 2.2 miles (3.5 km)) in ice cold waters. She was congratulated jointly by Mikhail Gorbachev and Ronald Reagan four months later at the signing of the INF Missile Treaty at the White House, when Gorbachev made a toast. He and President Reagan lifted their glasses and Gorbachev said: "Last summer it took one brave American by the name of Lynne Cox just two hours to swim from one of our countries to the other. We saw on television how sincere and friendly the meeting was between our people and the Americans when she stepped onto the Soviet shore. She proved by her courage how close to each other our peoples live". 
Eleven species of birds including such as puffins and guillemots  have been found on Big Diomede. In 1976 a rufous hummingbird was identified on the island.  This finding, unique so far in Russia, was very likely due to a dispersed specimen. For mammals, pinnipeds (e.g. ringed and bearded seals, walruses ) and cetaceans (e.g. gray and rarer bowhead whales) inhabit the waters around the island. 
- ru:Ратманов, Макар Иванович
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