According to Wikipedia:
112 (one-one-two) is the emergency telephone number in:
the European Union member states,
the Colombia (South America), and
worldwide on GSM mobile networks and their more modern equivalents.
In 1991, the European Union established 112 as the universal emergency number for all its member states. All EU countries have already implemented 112 and the number can be dialled free of charge from any telephone or any mobile phone. The GSM mobile phone standard designates 112 as an emergency number, so it will work on GSM phones even in North America where GSM system redirects emergency calls to 911 or Australia where emergency calls are redirected to 000. It is one of two numbers (the other being the region's own emergency number) that can be dialed on most GSM phones even if the phone is locked.
The number is now regulated across the EU by the Universal Service Directive.[1]