The Rijeka carnival is a really big party that happens every year in a city in Croatia called Rijeka. During this party, people dress up in super silly costumes and dance and sing around the city.
They have big parades that go through the streets and lots of music and dancing. Some people even make really big floats covered in cool decorations and they ride them through the city.
Everyone is really happy and having fun together, and it's a time when people can forget about their problems and just enjoy being with their friends and family.
It's kind of like Halloween, but instead of just going trick-or-treating, everyone goes outside and celebrates together. And everyone is welcome to join in on the fun, no matter how old you are!