Tourism stimulates infrastructure investment, such as construction of buildings, roads, railroads, airports, sewage systems, water-treatment facilities and other tourism-related facilities. Existing infrastructure may also be used in a manner which benefits local communities, where the tourist is using the facility in one way, while the community uses it in another. For example, a school may gain revenue from its use as a campground or conference venue. Improved and cheap transport services might also be brought to local communities by increased tourism.