On July 24, 2010, the denizens of planet earth were set a challenge. Asked to pepper YouTube with short films from a day in their lives, a melting pot of over 80,000 submissions was soon simmering online. Tasked with taking the footage and retooling it into a movie, Kevin MacDonald – with Ridley and Tony Scott on board as executive producers – set about crafting a movie designed to best showcase life in a day on our planet. From sunrise to sunset then, we witness all of the things that ultimately make us human, from the fulfilment of our base needs, to discussion of our loves and fears, to the miracles and tragedies that pervade every second of human existence.

As alarms ring out and weary feet meet the cold morning floor, all worries that a plotless, special-effects-less, melee of amateur home movies might struggle to compete with the usual barrage of summer juggernauts instantly subside. Life in a Day is anything but unstructured, with the careful selection and considered editing that has gone into the finished product lending it a pace and form all of its own. The film is bursting with characters too, with a number of individuals cropping up more than once in order to lend procedings a sense of continuity and consistency: a young shoe-shiner prepares for a day’s work; a man attempts to unite a divided Korea by circumventing the globe on his trusty bycicle – careless motorists permitting – and a mother convinces her son to partake in a family project in the hope of making the most of the little time she has left with those she loves.

The closest MacDonald comes to manipulating his charges is in the intermittent posing of questions – inciting confessions of a society’s greatest loves and fears, as well as the contents of each individual’s pockets – the answers ranging from the keys to a Lamborghini, a young girl’s “anti-evil eye protector” and an ageing farmer’s humbling declaration of nothing. For the most part, however, Life in a Day is a beautifully honest, uncontrived, relatively uncompromising depiction of our world. Babies are born, deaths are mourned, teeth are brushed, animals are slaughtered, rituals are practised and crimes are committed. A man comes out to his grandmother, an adolescent experiences his first shave and a woman contacts her husband abroad. Thrilling, you might easily scoff. But it is.

While a few well placed prompts and some careful editing might sate the eyes, it is still difficult to imagine how MacDonald might hope to craft a fully fledged and duly satisfying cinema experience out of a few grainy YouTube clips and a gimmicky cause. The truth is he doesn’t. Luckily, however, Harry Gregson-Williams, Matthew Herbert and the film’s astonishing sound mixing department are on hand to compliment the selected footage with a compelling and delightfully eclectic soundtrack, successfully providing the momentum the visual content cannot. Initially sung by Ellie Goulding, the film’s original song – re-recorded and repeated throughout the feature – helps guide the overarching mood propagated by the filmmakers without ever intruding on what amounts to a surprisingly personal experience.

Ambitious by its very nature, Life in a Day is as memorably extraordinary and as fleetingly mundane as any average day in the life. While there will be those who criticise the film on behalf of its positive skew, the filmmakers do an admirable job of portraying humanity at its best and at its very worst, commendably free of a political, social or religious agenda. At times joyous, cringe-worthy, gruesome, funny, harrowing and – as one young man chronicles his romantic rejection – heartbreaking, Life in a Day achieves its goal beautifully, encapsulating 24 hours of human history and creating a unique time capsule for the future.