* Part of a proper noun: For example, "World War II," "World Trade Organization," "New World."
* The first word of a sentence: "World peace is a goal we should all strive for."
* Used in a title: "The World According to Garp."
In other cases, "world" should be lowercase. For example:
* "The world is a beautiful place."
* "They traveled all over the world."
* "The world of finance is complex."