The United Nation's International Day of Happiness has taken place, and Secretary General Ban Ki-moon has released a video asking people to share the song that makes them smile.

To mark the occasion, singer Pharrell Williams addressed the UN and told those present that "happiness is your birthright".

A 2013 UN report ranked countries in order of happiness, putting Denmark in the top spot, with Europeans countries dominating the top 10.

Elaine Jung reports.