Finland is the world's happiest country – and professional "happiness hacker" Lena Salmi knows where to find Helsinki's happiest spots, from sea pools to graffiti walls. For the last seven years, Finland has been voted the happiest place in the world. Of the 140 countries surveyed in the UN's latest World Happiness Report , it continues to rank top for health, wealth, kindness and freedom for citizens to do as they please.

Never is that clearer than during the summer when daylight reigns in "the land of the midnight Sun", bringing the city’s unique blend of nature and urban perks to life. An archipelago framed by 300 islands, with two national parks reachable by public transport from the city and plenty of green spaces, Helsinki is an outdoor-lover's paradise and a sauna-goer's haven ; the city has one for every two residents. Add 19 hours of daylight to breezy summertime highs of 21C, and the "happiest city in the happiest country" moniker suddenly makes perfect sense.

We spoke with Lena Salmi , a professional "happiness hacker", to find the city's most happiness-inducing outdoor spots. Salmi – who helps visitors " find their inner Finn " through outdoor city tours – swims, scoots and skates her way through her hometown, doing the latter in a tutu, having taken up the sport seven years ago at the age of 63. Salmi worked in Finnish Lapland for decades as a sports journalist until she discovered her "hack" to happiness: "[I] recognised what I missed in Helsinki", she r.