A travel agency is a retail business, that sells travel related products and services, particularly package tours, to end-user customers, on behalf of third party travel suppliers, such as airlines, car rentals, cruise lines, hotels, railways, sightseeing tours and tour companies. In addition to dealing with ordinary tourists, most travel agencies have a separate department devoted to making travel arrangements for business travelers, and some travel agencies specialize in commercial and business travel only. There are also travel agencies that serve as general sales agents for foreign travel companies, allowing them to have offices in countries other than where their headquarters are located.