Company stock prices and the stock market in general can be affected by world events such as war and civil unrest, natural disasters and terrorism. These influences can be direct and indirect, and they often occur in chain reactions. The social uncertainty and fear generated by the terrorist attacks on Sept. 11, 2001, affected markets directly as they caused many investors in the United States to trade less and to focus on stocks and bonds with less risk. An example of an indirect influence on markets is the announcement of a new military venture by a country in response to the outbreak of civil unrest or conflict abroad. This announcement likely would cause the price of the stocks of military equipment and weapons manufacturers to rise due to an expected increase in defense contracts, which in turn can raise the value of stocks for companies that supply military equipment parts and technology. It likely would raise the demand for, and price of, natural resources used to make these parts, which would raise the price of stocks representing particular mining and natural resource processing companies.