while some other blocks still use the marchinha kind of music to create their own theme, most blocks tend to choose samba as their preferred music genre - in rio, the term bloco is used to define a variety of popular events, although normally it refers specifically to carnival related gatherings with music.

blocos can vary much in size and themes, ranging from gatherings of just a few hundred revelers, to immense gatherings of two million people - most have trucks with a band singing and dancing on top of it, while other blocks only have dj's, and some others don't have a truck but simply a band.