Prostitution is when people sell their bodies for sex with other people. In Europe, some countries have made it legal for people to sell sex as a job. This means that people who want to sell sex can do it safely and can get help if anything bad happens to them. But there are rules that they have to follow, like getting regular health check-ups and not working on the streets where it's not safe. In other countries, like England, selling sex is not illegal, but buying it is. This means that people who pay for sex can get in trouble with the police. Overall, prostitution is a complicated topic and every country has different rules about it.