The process of dialing a number and a telephone ringing on the other side of the world is very intersting. To me at least. It gets even more interesting when you think about how things like how to bill the call. The whole process is called ENUM.
I learnt some interesting things about the international country codes:
- Antartica has no country code instead you have to dial the country code of the particular base you wish to speak with
- The Vatican City has it’s own country code, but instead uses Rome dialing codes
- country codes 90 to 99 used to be used for intercontinental traffic before 1960
I started reading about this because I followed a link from the E.164 page. I like e.164 because it maps my telephone number to an ip address that can be looked up in dns.   So if you call me on my VOIP number from your VOIP provider the call is mapped to an ip addresses and never touches the PSTN.