“Why are you here?“ Gojira frontman Joe Duplantier asks the Sonisphere Finland audience. “I’ll tell you why you’re here… to lose your fucking minds to metal!”

The huge cheer which erupts from the Helsinki crowd suggests that the young Frenchman has gauged the mood of the day perfectly. For from the moment the gates are opened until the final ringing notes of Metallica’s set-closing anthem Seek And Destroy echo across the Kalasatama site, Finland’s denim and leather clad brethren – all 47,000 of them in this sold-out arena – sing loud and proud in their support of all things metallic. Truly, it’s one hell of a party.

In the run-up to the fourth stop on Sonisphere’s annual European adventure, the skies over Helsinki were grey, brooding and ominously studded with black clouds pregnant with rain, leading to fears of a repeat of the ferocious weather conditions which battered the Pori site in 2010. Happily, June 4 dawns clear and bright, and there’s not a cloud in the sky when Gothenburg’s HARDCORE SUPERSTAR get the party started at 3pm. Led by the irrepressible Jocke Berg – as good a frontman as will grace this stage today – the quartet are in fabulous form, serving up the muscular raunch ‘n’ roll of My Good Reputation and Wild Boys with wit and no little style.

Next up, GOJIRA simply crush Kalasatama into submission. The Heaviest Matter Of The Universe is beyond intense and L’Enfant Sauvage, the title track of the French four piece’s upcoming fifth studio album, suggests that the men from Bayonne are still finding inventive new ways to blow minds and speakers alike. Uncompromising and unrelenting, Gojira still sound suspiciously like the future of metal.

GHOST are less concerned about pushing boundaries and more focussed on re-conjuring the diabolical delights of cult heroes Mercyful Fate and Witchfinder General in Satan’s honour. It’s not easy performing a Black Mass under clear blue skies, but the mysterious Papa Emeritus and his nameless ghouls are a captivating presence in their pure white robes, and the likes of Stand By Him and set-closer Ritual manage to be both hauntingly beautiful and menacing all at once.

MACHINE HEAD almost didn’t make it to Finland today, as a cancelled flight from Germany threatened to leave the quartet stranded. But the Bay Area ‘Bangers have overcome bigger problems than this in their illustrious career and they make it onsite with just 45 minutes to prepare for their 7:30pm slot. Forced to use borrowed equipment and then cursed by technical gremlins, today could have been a nightmare for Oakland’s finest, but they power through a breath-taking set with sheer bloody-minded force of will. Drawing largely upon 2007′s masterful The Blackening set and 2011′s Unto The Locust, the quartet are in devastating form, and Aesthetics Of Hate and Halo incite some of the day’s most brutal pits. A triumph.

And so to the main attraction… METALLICA have been headlining festivals across the world for twenty years now, but their appetite for nights like this remains undiminished. And from the moment set opener Hit The Lights explodes from the speakers, it’s clear that tonight will be another enchanted evening in the four horsemen’s company. Everyone now knows that the quartet are showcasing their phenomenal ‘Black Album‘ on this European blitzkrieg, but the reality of hearing that killer five track run from Wherever I May Roam through to Enter Sandman is impossibly thrilling. From there we’re treated to a pyro-enhanced sprint through Fight Fire With Fire, a typically pulverising One and a celebratory set-closing romp through perennial live favourite Seek And Destroy, with that iconic chorus borne aloft by 47,000 hoarse voices. It’s a glorious end to an unforgettable day.

Same time next year then Helsinki?