The melding of American Jazz/Swing music and Cuban music in the mid 1940's created new rhythms and an opportunity for new forms of dance.
Mambo originated in Cuba and is often attributed to Perez Prado who introduced a version of the dance in Havana in 1943.
A modified and less acrobatic version was introduced in the late 40's in New York and was very popular into the early 50's.
The Latin Ballroom style of Mambo is a very easy and extremely versatile dance. The freestyle form is a slow, precise spot dance that generally moves forward and back and is ideal for small dance floors.
As Mambo was one of Cha Cha's 'parent' dances the two dances share many similarities in steps and style. Given this close relationship, Mambo can also easily be used as a slower substitute for fast Cha Cha music.
In the 1990's, Latin American dancing enjoyed a revival and Mambo as a dance has again become popular. In its current incarnation, it is increasingly becoming known as LA Salsa.
In this form, it has a more sensual and fluid body rhythm and is danced more smoothly, quickly and compactly to modern Latin music, but still follows the general step patterns, timing and forward and back movements characterizing Mambo.
LA Salsa is related, but quite different to Cuban Salsa.