One of the first targets of law enforcement actions against illegal prostitution is to find the people who force people into prostitution. This is called sexual slavery. Sex trafficking is when people are taken somewhere in order to be a prostitute. It might be done by forcing them or by tricking them in some way. Sex trafficking is one type of Human trafficking. Some people have called human trafficking "the fastest growing form of modern-day slavery", and the third largest and fastest growing criminal industry in the world.