Infrastructure refers to structures, systems, and facilities serving the economy of a business, industry, country, city, town, or area, including the services and facilities necessary for its economy to function. It is typically a term to characterize the existence or condition of costly 'technical structures' such as roads, bridges, tunnels, or other constructed facilities such as loading docks, cold storage chambers, electrical capacity, fuel tanks, cranes, overhead clearances, or components of water supplies, sewers, electrical grids, telecommunications, and so forth. Infrastructure thus consists of improvements with significant cost to develop or install that return an important value over time.