Prostitution is the act or practice of providing sexual services to another person in return for payment. People who execute such activities are called prostitutes. Prostitution is one of the branches of the sex industry. The legal status of prostitution varies from country to country, from being a punishable crime to a regulated profession. Estimates place the annual revenue generated from the global prostitution industry to be over $100 billion.
Prostitution occurs in a variety of forms. Brothels are establishments specifically dedicated to prostitution. In escort prostitution, the act takes place at the customer's residence or hotel room (referred to as out-call), or at the escort's residence or in a hotel room rented for the occasion by the escort (called in-call). Another form is street prostitution. Sex tourism refers to travelling, typically from developed to under-developed nations, to engage in sexual activity with prostitutes.