Carnival is not only celebrated in Brazil, but in a good part of the planet.
See below the main celebrations.
UK
During the Brazilian carnival period, the Shroveitide (Shrive which means to confess 'sins') takes place in the United Kingdom, which is the celebration of the British carnival.
U.S
In the United States, carnival is basically summed up in the celebration of Mardi Grass (Fat Tuesday), several states celebrate carnival.
The most traditional state in the commemoration is New Orleans, where, during Mardi Grass, more than 50 associations parade through the streets. The best known association is that of Bacchus (which has gigantic and original floats).
Germany
In Germany, the celebration of carnival takes place both in large urban centers and in the Black Forest and the Alps.
The most traditional festival is in the city of Bonn, which organizes parades with costumed people; the devil gets loose, for that reason people wear masks to hide their faces.
Venice
For a long time, the Venetian carnival was one of the strongest and most joyful in the world. During the Carnival period, dances and parties were held in the city's squares and streets. As time went by, Venice's carnival was weakening, reaching almost extinction.
Source: Brazil School - https://brasilescola.uol.com.br/carnaval/carnaval-do-mundo.htm
