Old-fashioned weapons still kill many people in wars and fighting. In wars in Africa in the 1990s and early 21st century, many people were killed with machetes (big knives). People sometimes try to make laws, treaties, and international agreements to try to control weapons because they are worried about all the killing done with them. Laws vary from country to country, for example, in the United States, the "right to keep and bear arms" is guaranteed to all citizens by the Constitution. A country may say that people in that country cannot keep or use guns, or only when the government allows it. The laws of war forbid certain weapons, and countries may agree with each other that they should not use certain weapons against each other, or should not have more than a certain number of particular kinds of weapons.