Although optional for travelers, you should register your trip with the federal government of your home country.
For example the“Smart Traveler Enrollment Program” (STEP) website run by the US State Department allows US citizens to enter information about an upcoming trip abroad. You enter details such as your travel dates, destination(s), address abroad, emergency contact and more.
In case of an emergency abroad, the Department of State can better assist you in an emergency. What kind of emergency? Natural disasters like an earthquake or tsunami; or civil unrest following an election. Registering with STEP could also speed up the process of replacing your lost passport while abroad.
As an added service, STEP can also send you electronic updates on travel warnings, travel alerts and other information for the country you’ll be visiting.
Websites for registering your trip abroad
US Citizens: https://step.state.gov/step
UK Citizens: http://www.fco.gov.uk/en
Canadian Citizens: http://www.voyage.gc.ca
Australian Citizens: http://www.orao.dfat.gov.au
French Citizens: http://www.diplomatie.gouv.fr/en
South Africans: http://www.dfa.gov.za/consular/travel_advice.htm