I’ll say this much for CPH:DOX: it’s the only festival where I’ve attended a screening inside a disused reservoir. The building that used to house Copenhagen’s drinking water stocks has since become an underground arts venue – the perfect place for an atmospheric staging of Rob Petit’s Underland, adapted from Robert Macfarlane’s best-selling non-fiction book about the strange worlds that team with life beneath our feet. While narrator Sandra Hüller’s dulcet tones echoed around the cavernous, deceptively cold space, the audience huddled under blankets, clutching cups of tea for warmth. It was the sort of immersive experience I always appreciate at a film festival…at least until the screen suddenly malfunctioned five minutes before the end (as is sometimes the pitfall of unconventional screening spaces). 

Despite this hiccup, there was a jovial atmosphere in the room, and Petit’s hypnotic film brought distant cave networks and secret dark matter research stations closer than ever, while revealing these same spaces and ideas have fascinated humans for as long as we’ve existed. The underground connects us not only with nature, but while everything that has gone before. While waiting for the bus back into town – contending against the force of a vicious Nordic gale – I pondered the nature of connection within the film festival itself, and how the films that stood out to me the most seemed to echo the theme of revelation in one way or another. With the idea of hidden truths in mind, here are five documentaries that stood out from the pack this year at one of the world’s finest documentary showcases.