Denmark overtook Switzerland as the world's happiest place, according to a report released on Wednesday that urged all nations, regardless of wealth, to tackle inequality and protect the environment.

Economic stability is a big factor in the ranking…

Swiss in 2nd place on worlds happiest countries list 2016

The top five countries on the list all happen to be located in northern climes. Here, Swiss skier Fabienne Suter soars above the course in St. Moritz on March. 15. (Matthias Hangst/Getty)

…but social support and solidarity are significant yardsticks, too.

The World Happiness Report, now in its fourth edition, is prepared by the United Nations-backed Sustainable Development Solutions Network (SDSN) and the Earth Institute at Columbia University, and ranks 157 countries by their happiness levels. It was released Wednesday in Rome in advance of UN World Happiness Day, on March 20.

Norway top 5 worlds happiest countries list 2016

Norway is in fourth place between its Nordic neighbours Iceland and Finland. (Olivier Morin/AFP/Getty)

Canada dropped one place from last year

The top 10 this year are Denmark, Switzerland, Iceland, Norway, Finland, Canada, the Netherlands, New Zealand, Australia and Sweden. Denmark was in third place last year, behind Switzerland and Iceland.

The United States came in at 13, the United Kingdom at 23, France at 32 and Italy at 50.

Canada beats US on worlds happiest countries list 2016

Prime Minister Justin Trudeau visited the White House on March 10, but not to gloat. (Jim Watson/Agence France-Presse)

The unhappiest countries are…

The bottom 10 are: Madagascar, Tanzania, Liberia, Guinea, Rwanda, Benin, Afghanistan, Togo, Syria and Burundi, which is last in 157th place.

happiness index BURUNDI-last place 2016

The Republic of Burundi, located in central Africa, is in the midst of a violent political crisis. (Goran Tomasevic/Reuters)

Syria has ranked consistently low.

How it works:

The survey aims to measure "the scientific underpinnings of subjective well-being," according to Professor Jeffrey Sachs, who heads up the SDSN and serves as a special advisor to UN Secretary General Ban Ki-moon.

The rankings are based on factors such as per capita gross domestic product and healthy years of life expectancy, as well as more intangible elements like "having someone to count on in times of trouble" and freedom from corruption in government, Sachs said in an interview with Reuters.