While commonly associated with Nazi Germany, the swastika symbol is more than 3,000 years old. The term "Swastika" was originally the name for a hooked cross in Sanskrit, and swastikas have been found on artifacts, such as coins and pottery, from the ancient city of Troy.
Not only are swastikas associated with ancient Troy, the symbols are found in many other cultures, such as Chinese, Japanese, Indian and southern European. By the Middle Ages, the swastika was a well-known symbol and had many different names, depending on the country. In some cultures, such as in ancient China, the symbol is turned counterclockwise (sauvastika).
Throughout its history, the swastika represented life, sun, power, strength and good luck. In the early 20th century, it was still considered a positive symbol. During World War I, it was found on shoulder patches of members of the American 45th Division and the Finnish air force. Only after the Nazi period did its connotation change.
German nationalists chose to use the swastika in the mid-19th century because it was associated with the Aryan race and Germanic history. At the end of the 19th century, German nationalists used the symbol on periodicals and for the official emblem of the German Gymnasts’ League. By the 20th century, it was a common symbol used in Germany to represent German nationalism and pride, for example, as the emblem for the Wandervogel, a German youth group. Swastikas also were used, however, in anti-Semitic periodicals.
The swastika officially became the emblem for the Nazi Party on August, 7, 1920, at the Salzburg Congress. Describing the new flag in Mein Kampf, Hitler said the swastika symbolized the victory of the Aryan man.
Today the symbol is most commonly associated with Nazi Germany, the Holocaust, neo-Nazis and other hate groups.
Sources: "The History of the Swatiska."