What you are looking at is float during the Brazilian Carnival in Salvador. In Portuguese they call them Blocos (pronounced Blouckus) this is one of the ways that you can enjoy the Carnival. You can either pay to join the bands at the top or walk along the roped off area that is controlled by security on the floor.
If you pay to be in the top of the float (Bloco) then you won’t be able to leave but if you pay to be on the floor then you can go inside and outside of the roped off area. Click here for more pictures of Brazil & check out the top 5 section for more things to do in Brazil & around the world.