People have been on move since prehistoric times, initially to find food, territory, for trade, exploration and pleasure. The word travel originates from the Middle English word travailen which means "to toil", which comes from the Old French word travailler "travail". A person who travels is called a traveller. In some instance people have moved places to escape danger or oppression. Travel may be local, regional, national (domestic) or international. In certain countries, they insist for internal passport within the country, while international travel typically requires a passport and visa. Travel may occur by human-powered transport such as walking or bicycling, or with vehicles, such as airplanes, private transport, public transport, automobiles and trains. However, it is only since the 19th century, with the advent of new efficient methods of transport, that the mass travel has become widely available. The first travel agency was opened in the year 1850. Since then, a large industry has developed devoted to organizing tours, booking tickets and hotels, and insuring holiday markets.