History of Switzerland
Switzerland's most important exports during the war were precision machine tools, watches, jewel bearings (used in bombsights), electricity, and dairy products. During World War Two, the Swiss franc was the only remaining major freely convertible currency in the world, and both the Allies and the Germans sold large amounts of gold to the Swiss National Bank. Between 1940 and 1945, the German Reichsbank sold 1.3 billion francs worth of gold to Swiss Banks in exchange for Swiss francs and other foreign currency.
Banknotes of the Swiss franc
Switzerland is unusual among affluent countries in that it expires its banknotes; the Swiss National Bank has declared several older series of banknotes to be no longer legal tender some time after introducing newer series. Notes from these "recalled" series can be exchanged for still-valid notes at the National Bank for up to 20 years after the date of recall, after which the notes lose all value. When recalled series become valueless, the National Bank transfers an amount of money equal to the sum of the now-worthless notes to a state-run last-resort disaster insurance fund, the Swiss Fund for Aid in Cases of Uninsurable Damage by Natural Forces. The most recently recalled series of banknotes, the sixth series, was recalled on 1 May 2000 and will expire on 1 May 2020. The Swiss Federal Council (executive cabinet) and National Bank have proposed to remove this twenty-year time limit for the sixth series as well as any future recalled series; as of mid-2018, this proposal remains in the draft bill stage.