Before 1932 the SS wore the same uniform as the SA, except for a black tie and a black cap with a skull symbol on it (Totenkopf, "death's head"). Later they adopted a black uniform and then, just before the war, a field grey uniform.
Heinrich Himmler, together with his right-hand man Reinhard Heydrich, consolidated the power of the organisation. In 1931 Himmler gave Heydrich the assignment to build an intelligence service inside the SS, the Sicherheitsdienst.
By the time World War II began the number of members rose to 250,000 and the Waffen-SS was formed in December 1940 to fight alongside the Wehrmacht, Germany's regular military. The SS also received control of the Gestapo in 1936.
The SS evolved into a highly effective and deadly force during World War II. At its peak, its name and reputation for efficient and terrifying violence was enough to strike fear into the heart of anyone. Hitler gave the SS jurisdiction over all concentration camps and allowed them to oversee the day-to-day control of all countries conquered by Germany during the war.
Towards the end of World War II, a group of former SS officers went to Argentina and set up a Nazi fugitive network code-named ODESSA (an acronym for Organisation der ehemaligen SS-Angehörigen) with tentacles in Germany, Switzerland, Italy and the Vatican, operated out of Buenos Aires, which helped Adolf Eichmann, Josef Mengele, Erich Priebke and many other war criminals find refuge in Latin America.
See also: Praetorian Guard, Secret Service