Why are there carnivals?
Carnivals —like in Rio de Janeiro, Barranquilla, Salvador, Venice or Cajamarca— are a few days in which everybody lets loose. People drink, dance, party, wear costumes or organize authentic festivals which summon not only the locals but thousands of people from all over the world.
Why? Well, carnivals exist for religious reasons: They are a few days before the beginning of Lent, on Ash Wednesday.
During Lent, Christians are invited to prayer, penitence, alms giving, contrition, and some fasting for forty days until the start of the Holy Week.
Carnivals are a farewell. Actually, the word carnival comes from the Latin voice "carnevale", which means "good-bye meat". Maybe that's why carnal excesses are, say, very common.
Knowledge + Why?