1.  Members of the United Nations (193 of them):

http://www.un.org/en/ga/

2.  Europa World Plus:  information (political, social, financial, education, etc) on countries arranged by continent:

http://www.europaworld.com/welcome?authstatuscode=200

3.  CIA World Fact Book:

https://www.cia.gov/library/publications/the-world-factbook/index.html