So I had no idea what to expect going into Carnaval, because I did not do any research and I like to be surprised. But I definitely went in with guns loaded. And I'm exhausted. I came in with the impression that it was a festival that would last 4 days, much like the New Orleans counter part Mardi Gras, which I experienced last year. However, do not be fooled. Carnaval is not a 4-day long party.. It's actually a month long party (pre-Carnaval and post-Carnaval parties are abundant, especially the weeks leading up to the actual, registered dates), and even the toughest of party animals will have to give up or take breaks at some point.
Carnaval consists of Escolas da Samba (schools of Samba) and shows of some kind and Blocos (block parties)
I will be elaborating on the blocos because I did not go to any escolas da samba this time because they cost money, and the alternative, Blocos are free.
Blocos occur everywhere throughout the city. There should be a mobile app that tells you when and where they will occur. Blocos include music- a band, always accompanied by a large percussion section, and they are themed. Some blocos are huge, and you need to be careful of pickpockets, some are small and relatively underground/hipster in nature. But all blocos are a good time.
What you need to know:
Be prepared to sweat
Wear a costume.
Be prepared for someone to kiss your face
Prepare for heat.
Carnaval falls in February, which is summer in Brazil, and in Rio it gets hot! Triple digits on the Fahrenheit scale, +40 on the Celcius. Although some relief can be had thanks to the various vendors selling 'picoles' and 'sacoles' in the street (like popsickles or 'sacks' of frozen drink, respectively, usually containing alcohol). You can also almost always find someone selling cold beer and perhaps even more importantly water.
Wear sunblock if you are susceptible to burn, and make sure to use common sense wth the costume you choose. Which brings me to the next point.
Wear a costume.
Going in, I did not realize that Carnaval is like a counterpart to Halloween- well more like many consecutive Halloweens that last day and night. You are not required to wear a costume to enjoy Carnaval, but it makes it more fun. People will relate to you and it will spark conversations, especially if you are by yourself, and even if you do not speak the language. It may be overwhelming to imagine planning a different costume for each day.. but don't worry, it's ok to recycle costume- but at least try to have two or three.
Prepare to be kissed.
Besides the typical double kiss on the cheeks which is customary in greetings and departures in Carioca culture, people are extra friendly during Carnaval. If you catch eyes with someone you are attracted to, and the feeling is mutual, after a rather prolonged initial staredown and possibly a brief introduction, a makeout session may spontaneously ensue. It doesn't matter that you are in the middle of a bloco of possibly thousands of people, many of whom may be doing the same; in Carnaval, there is no shame for a little show of affection for new aquaintances. It's part of the allure of the festivities, and it is not uncommon for this firey exchange to come and go without ever knowing each others' names, so don't feel heartbroken when the pirate or cat of your dreams bids you fairwell to go to another bloco, just keep dancing and smiling and everthing will be "beleza."