Emergency numbers: what is it, and should you take it with you on a trip or while backpacking?

What is an emergency number?

An emergency number is a number you call when something happens that requires your help, and in case of an emergency.
This can relate to your health, a car accident, a local disaster, political unrest or if you are really in trouble.
An emergency number is also called an alarm number.
Embassies, insurers, banks and roadside assistance, among others, often have an emergency number. You can usually find this on the website, or by calling the agency.

To make use of local help: such as the police, ambulance, fire brigade. There is often a joint number such as 112 in Europe, 911 in the US and Canada and 000 in Australia. Some countries do not have an emergency number.
If you want to go to a local hospital or need medical help: many hospitals have their own emergency number. There are also poison control centres that have emergency numbers. For mental health: some countries have psychiatric crisis lines.
If you lose your passport, are arrested, a major disaster occurs or there is political unrest, you can often call the embassy or consulate emergency number.
As a medical backup: for example, if you need medical help but don't know where to go or what to do, you can call the emergency number of your travel insurance.
If your car breaks down: you can often call the emergency center of your car insurance or travel insurance.

Always! It is always wise to save important emergency numbers locally (i.e. in your phone or in a book) before you leave for a foreign country.
Some countries also have an emergency number specifically for tourists. This can be useful to save because of the language barrier you might otherwise encounter.