Warped, twisted and riddled with fractures, Senja's mountains conceal a million expressive faces. But of all the peaks tearing from Northern Norway's coastline, one summit stands out in particular; gazing towards the tempestuous Norwegian Sea, a pendulous nose sagging below matted hair, it's even been recorded in the book of Guinness World Records.

When Leif Rubach started building Finnsaeter's Senjatrollet in 1993, he had no idea his childhood fantasy would grow into one of the island's most curious tourist attractions. Celebrating its 25th anniversary earlier this month, the world's biggest manmade troll towers 17.96 metres, and to date, its hegemony is unrivalled.

A source of fascination throughout Scandinavia, trolls could find no better home than Senja, an island sitting above the Arctic Circle which is connected by bridge to the mainland. Often described as Norway in miniature, it has all the natural attractions drawing people to the country - creating plenty of places for fairy-tale characters to thrive.

Inside the world's biggest troll

"Trolls are everywhere," grins softly spoken Leif, now in his 70s, who is up a ladder making final adjustments to his latest family addition, "the sextuplets" - six teenage trolls.

"You find them up mountains, in forests and out at sea."

Growing up in small fishing village Gryllefjord, Leif first encountered the gnarly creatures on boat trips with his uncle, and in the absence of electricity, dark evenings were spent listening to local legends and fantastical tales told by candlelight.

Many of those stories have inspired grottoes built inside the giant troll. The Mitten Trolls recalls warnings parents would give their children about mini beasts sleeping in fishermen's gloves pinned to boat houses - an attempt to keep them away from dangerous quays. More macabre, a tableau of two brothers feeding fish with human flesh is supposedly based on a true story recounted by an 18th century priest.

Dressed in a knitted fisherman's jumper covered in plastic spiders and hessian dungarees with a cow tail, Leif has assumed the role of troll father, and even has his own throne. His wife, Siw, who he married at Senjatrollet, writes books and works in the souvenir shop, selling CDs from Leif's band, The Trolling Stones, who perform here daily during summer.

"Just the other day, someone told me they'd seen Hulder," Siw whispers conspiratorially, referring to the supernatural siren from Norwegian folklore. She says it without a hint of irony, and I know she believes it's true.

The land of midnight sun

A short distance from Finnsaeter, Hamn I Senja hotel overlooks the Bergsoyan archipelago, a cluster of coral mounds looped by turquoise waters and a favourite resting point for seals and sea eagles.

From the top of Sukkertoppen mountain, I have a clear view of the landscape - a gnarled, outstretched hand reaching into the sea, with fjords running gently through its fingers. Defiant streaks of snow cling to crags, marking a switch between seasons, and moulting hares bolt through the russet gorse in their mismatched pyjamas.

It's midnight - way beyond their bedtime - but the sun still hasn't set; it won't for another few months. Instead, it gently dips and kisses the horizon, leaving a coral lipstick stain that lasts for hours.

With so much light, the opportunities to explore are endless. Going to bed just seems like a waste of time.

Energised, I drive for half an hour to Steinfjord, through tunnels hewn into rocks seemingly crawling with trolls. At Tungeneset, a wooden walkway leads to the water and a perfect viewing platform for the Devil's Teeth, a series of serrated rocks biting at the sky - one of the most photographed spots in Norway. Gulls surf on fierce waves thrashing at the rocks, and in the dead of day-night, it's just me and the ocean.

A tower on top of the world

While Senja's dramatic scenery is concentrated in the north, the south of the island is equally alluring - and much more sheltered. Upturned boats rest off the shores of motionless lakes displaying perfect mountain reflections, in a place where shops and service stations seem few and far between.

Former city-dweller Hege Dekkerhus spent five years falling in love with Senja, eventually buying Camp Tranoybotn on the edge of Anderdalen National Park a year ago. Beyond the caravans and clapperboard cabins, a white tower for two sits on the water's edge, it's 360-degree windows filled with views of mountains and sea.

Inside, the theme is nautical; fishing net curtains, decorative glass teardrop buoys and hanging rails made from wooden oars. At low tide, screaming sandpipers pick for insects, and seaweed clinging to granite boulders reminds me of Leif's trolls.

An island with secrets to reveal

The number of islands in this fjord makes it perfect for kayaking, and Hege describes her daily paddles as a form of meditation. We make a trip to Tranoya, an island only reachable by boat, which has been inhabited by communities for nearly 2,000 years and has remains of a Viking boathouse.

Aside from caretaker Chris David Edwards and one long-term resident, only wild sheep roam the fields and forests, where bones, buttons and arrowheads are regularly unearthed.

Sitting alongside grass-roofed cottages, a wooden church from 775 contains an original altar and pulpit - both remarkably colourful for their time. In the neighbouring priest's house, Chris David casually shows me a room locked for almost a century until two years ago; peeling flock wallpaper and surprisingly sturdy wooden beams still have so many secrets to reveal.

Back at Camp Tranoybotn, Hege excitedly tells me about her plans to convert traditional fishing boats into accommodation. In an outhouse filled with reindeer skins, she also hopes to start storytelling sessions.

With so much history to draw upon, she'll have no shortage of material, and in a place like Senja, imaginations can easily run wild. After a few days, even trolls don't seem so far-fetched from reality. After all, anything can happen in the land of midnight sun.

How to get there

A stay in the Lighthouse at Camp Tranoybotn costs £220 per night. Visit norwegianwild.no.

A stay in Hamn I Senja costs from £64 per night with breakfast. Visit hamnisenja.no.

Norwegian flies to Tromso from London Gatwick. Prices start from £123.80 return. Visit norwegian.com/uk.

For more information on the destination, visit nordnorge.com/en.