Some websites that have a list of all the countries in the world are InfoPlease.com, State.gov, ProjectVisa.com and NationsOnline.org. There are 196 countries in the world as of November 2015, although some sources differ on whether regions such as Palestine, Pitcairn Island and Taiwan count as official countries.
InfoPlease provides country profiles that include its current ruler and capital. This source stars Palestine and Western Sahara as proposed states. The site lists Taiwan but notes that some countries do not recognize it as a country because China considers Taiwan a breakaway province.
The U.S. Department of State lists countries "and other regions." Clicking on a country shows its flag, links for the U.S. Ambassador to that country and a U.S. bilateral relations fact sheet.
ProjectVisa gives the continent or other region — such as the Caribbean — for each country. Clicking on a country leads to visa information for that country. Some islands, such as Wallis and Futuna Islands, have a listing here that is not on other country lists.
Nations Online lists as countries some islands that are connected to the Internet, such as Pitcairn Island. It provides a profile for each country.