Finnish people may be some of the happiest in the world but they also have several unusual traditions. Here are 5 surprising facts about the world's happiest country.

• Finland has been ranked the world's happiest country for the last six years.
• The country benefits from high levels of social trust and a strong connection with nature.

Finland is known for being the happiest country in the world, but there's a lot more to the Nordic nation than the yearly rankings.

The sparsely populated country has a landmass similar to that of New Mexico but a population of just over 5 million people — around 3 million less than New York City.

Finns endure harsh winters, drink a lot of coffee, and can be a bit pessimistic. Finland is also known for its saunas and strong welfare state, and it has several unusual traditions and social norms.

Here are five of the most surprising things about the country.

1. Speeding tickets are based on your income

In Finland, speeding fines are based on how much money a resident makes, along with how fast they were driving.

The country has a "day fine" system, which is calculated from the offender's daily disposable income and how far over the speed limit they were going.

The system has led to some eyewatering fines. Earlier this year, a Finnish multimillionaire was fined €121,000, or $129,400, for going over the speed limit.

2. There's around half a sauna per person

Tourist site Visit Finland estimates that there are three million saunas in Finland — or the equivalent of just over half a sauna per Finn.

Sauna culture is an important part of Finnish daily life and cultural heritage, and you can find saunas in apartment blocks, homes, restaurants, and even government buildings.

3. The Finnish government gives all new families a "baby box"

Finland's maternity package — known as äitiyspakkaus or as a "baby box" — is a kit sent by the government to the parents of newborn children.

The box contains essential items such as clothing, bibs, diapers, and bathing products, among other things. The box itself is fitted with a small mattress and a sheet so it can double up as a safe place for a newborn to sleep.

The boxes have proved popular in other countries, including the US. However, unlike in Finland, US parents have to pay for the box.

4. The country is home to a sport called "wife-carrying"

Wife-carrying is now an international sport, but the world championships are still held in Sonkajärvi, Finland.

The sport traditionally involves a male partner carrying their wife on their back while they complete an obstacle course. The rules have evolved slightly over the years and competitors don't have to carry their real spouses.

However, the "wife" has to be at least 17 years old and weigh a minimum of 49 kilograms. If the female partner is lighter, officials will weigh her down with a rucksack.

5. Finns have a word for staying in and drinking in your underwear

"Kalsarikännit" translates to drinking at home, alone, in your underwear.

Other untranslatable Finnish words include "vahingonilo," which means to enjoy someone else's misfortune, and "sisu," which is a kind of stoic determination or a tenacity of purpose.