World War II: The destroyer USS Reuben James is torpedoed by a German U-boat near Iceland, killing more than 100 U.S. Navy sailors. It is the first U.S. Navy vessel sunk by enemy action in WWII.

USS Reuben James (DD-245) was a four-funnel Clemson-class destroyer that was constructed after World War I. She was the first United States Navy ship to be named after Boatswain's Mate Reuben James, who had distinguished himself fighting in the First Barbary War, and was the first US navy ship to be sunk by hostile action in the European Theater of World War II. Four US flagged merchant ships were also sunk by hostile action before Pearl Harbor.

Nazi Germany, officially the German Reich and later the Greater German Reich, was the German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a totalitarian dictatorship. The Third Reich, meaning "Third Realm" or "Third Empire", referred to the Nazi claim that Nazi Germany was the successor to the earlier Holy Roman Empire (800–1806) and German Empire (1871–1918). The Third Reich, which the Nazis referred to as the Thousand-Year Reich, ended in May 1945, after 12 years, when the Allies defeated Germany and entered the capital, Berlin, ending World War II in Europe.

U-boats are naval submarines operated by Germany, including during the First and Second World Wars. The term is an anglicized form of the German word U-Boot, a shortening of Unterseeboot. Austro-Hungarian Navy submarines were also known as U-boats.

Iceland is a Nordic island country between the Arctic Ocean and the North Atlantic Ocean, located on the Mid-Atlantic Ridge between Europe and North America. It is culturally and politically linked with Europe and is the region's westernmost and most sparsely populated country. Its capital and largest city is Reykjavík, which is home to about 36% of the country's roughly 390,000 residents. The official language of the country is Icelandic. Iceland is on a rift between tectonic plates, and its geologic activity includes geysers and frequent volcanic eruptions. The interior consists of a volcanic plateau with sand and lava fields, mountains and glaciers, and many glacial rivers flow to the sea through the lowlands. Iceland is warmed by the Gulf Stream and has a temperate climate, despite being at a latitude just south of the Arctic Circle. Its latitude and marine influence keep summers chilly, and most of its islands have a polar climate.