The swastika has an extensive history. It was used at least 5,000 years before Adolf Hitler designed the Nazi flag. The word swastika comes from the Sanskrit svastika, which means “good fortune” or “well-being.” The motif (a hooked cross) appears to have first been used in Neolithic Eurasia, perhaps representing the movement of the sun through the sky. To this day it is a sacred symbol in Hinduism, Buddhism, Jainism, and Odinism. It is a common sight on temples or houses in India or Indonesia. Swastikas also have an ancient history in Europe, appearing on artifacts from pre-Christian European cultures.
Following a brief surge of popularity in Western culture, the swastika was adopted as a symbol of the National Socialist German Worker’s Party (the Nazi Party) in 1920. After Adolf Hitler’s rise to power in 1933 the Swastika became a commonly used symbol of Nazi Germany; in 1935 the Nazi Party Flag, which incorporated a Swastika, was made the sole State Flag of Germany. As a result in the western world the Swastika has been strongly associated with Nazism and related ideologies such as Fascism and White Supremacism since the 1930s. Its use is now largely stigmatized in the west; it has been outlawed in Germany if used as a symbol of Nazism.
Source: Wikipedia, US Holocaust Memorial Museum