Brazilian Jujutsu (BJJ) was formed from the Judo fundamentals of ground work (newaza).
Eventually BJJ became its own combat sport and was widely popularised by the Gracie family from Brazil. It promotes the concept that the smaller, weaker person can successfully defend themselves by use of proper technique and leverage with the application of joint locks and chokes.
The first BJJ school opened in Brazil in 1909. In 1917 Carlos Gracie saw a demonstration and decided to learn 'judo'. His sibling Helio Gracie further developed Gracie Jujitsu(Jiu-Jitsu) as a more groundwork sport. Since then it has spread worldwide.
There are now many tournaments held around the world where practitioners can pit their skills against others in a sport orientated and refereed system.