Samba is a lively, rhythmical dance of Afro-Brazilian origin in 2/4 time danced to Samba music whose origins include the Maxixe.
Samba is a dance authentic to black/African people in Brazil who brought much of their music and dance culture into Latin America with, them upon arrival into many Latin American countries. Samba music is very similar to and has been influenced by many Angolan music genres. It has also been influenced by many other Latin American music genres and dances. The Samba music rhythm has been danced in Brazil since its inception in the late 16th century. There is actually a set of dances, rather than a single dance, that define the Samba dancing scene in Brazil; however, no one dance can be claimed with certainty as the "original" Samba style.
Another major stream of the Samba dance besides the Brazilian Samba dancing styles is Ballroom Samba, which differs significantly.
Samba no pié (literally, "samba in the foot") is a solo dance that is commonly danced impromptu when samba music is played. The basic movement involves a straight body and a bending of one knee at a time. The feet move very slightly - only a few inches at a time. The rhythm is 2/4, with 3 steps per measure. It can be thought of as a step-ball-change. It can be described calling it and-a-one, and-a-two, then back to one. The basic movement is the same to either side, where one foot moves to the outside lifting up just before the first beat (i.e. the right leg moves slightly to the right) and leg is kept as straight as a pole. The other foot moves slightly towards the front, and closer to the first foot. The second leg bends lightly at the knee so that the left side of the hip lowers and the right side appears to move higher. The weight is shifted to this inside foot briefly for the next "and-a", then shifted back to the outside foot on the "two", and the same series of actions is repeated towards the other side.
The dance simply follows the beat of the music and can go from average pace to very fast. Men dance with the whole foot on the ground while women, often wearing heels, dance just on the balls of the foot. Professionals may change the steps slightly, taking 4 steps per measure instead of 3, and often add various arm movements depending on the mood of the music.
There are also regional forms of the dance in Brazil where the essential steps are the same, but because of a change in the accent of the music people will dance similar movements to the slightly changed accents. For instance, in Bahia the girls tend to dance tilting their legs towards the outside instead of keeping their knees close to each other as in Rio de Janeiro.