i believe krav maga was born in 1926 in czeckoslovakia, in the jewish ghettoes by a psychologist who studied the natural human reactions to fear, and threat.
his idea was to use the reaction of the human and employee that reaction to be able to get out of dangerous threatening situations without having to be trained.
the founder, IMI LECHTENFELD (not sure of spelling the last name) imported some moves from different arts, like Judo for instance. He employed krav maga in fights in the ghettoes of Bratislava and kept iterating through the techniques making them better and more effective.
Krav maga was taught to the jewish gangs in palestine in the late 30's and 40's until it became mature enough to be adopted by the jewish state of Israel.
later on krav maga adopted the belt system to be classified as an official martial art in the 60's. i believe they have a no-belt, yellow, orange, green, blue, brown, then two degrees of black belt.
they have different programs that are civilian, law enforcement, and instructor programs. I am sorry I am not sure what differs between them.
i know they only have 2 stances though

only 2!
it's supposed to help the kids, ladies, the disabled, and the drugged to defend themselves against any weapon and under any condition.
the question that I have is: is it as strong as advertised? or it only has good marketing?