Once, Folkestone was a destination. Authors from Charles Dickens to Agatha Christie found inspiration in the town and so popular was it with those with money and leisure that a bar in the Grand Hotel is named after Mrs Keppels, the mistress of once frequent visitor Edward VII. It's hard to imagine its glory days now. Like so many other seaside towns, which fell out of favour in the era of cheap overseas holidays, it's enjoyed better times. The opening of the Channel Tunnel saw off ferries to France and even the Orient Express, which until recently passed through Folkestone on its way to the continent, has ceased to stop at the harbour station. In the past few years, a new (extremely ugly) shopping centre has been built in an attempt to revitalise the declining town centre, and the Folkestone Triennial initiated, aiming to reinvigorate the town culturally.
The first festival, in 2008, installed works by leading artists in prominent places around the town, inspired by both Folkestone's heritage and the cultural baggage of seaside towns – from teen pregnancy to pigeons. Some of the artworks have become permanent, and settled into the fabric of the town – Richard Wentworth's plaques denoting non-native tree species, Tracy Emin's casts of discarded children's items, Mark Wallinger's cliff-top pebbles commemorating the lives of local men lost in the first world war and Richard Wilson's beach huts, refashioned from a former crazy golf course. The second Folkestone Triennial builds on the first, with international artists opening up the town's hidden, deserted and overlooked places (whether through dereliction, decline or obsolescence), from lowly back rooms and storage spaces to a grand Masonic Hall. I went to secondary school in Folkestone, and the Triennial is not just an art treasure hunt, challenging you to find works scattered about the town, but an alternative guidebook, taking you from the West End to the East Cliff and giving a new perspective on the sights in between.
One space usually unseen by the public is a dank, dark deckchair store underneath the cliff-top Leas promenade, where French-Algerian artist Zineb Sedira's films play on mismatched video screens around the room in an effective, immersive installation. Her films document two Algerian lighthouses and the sometimes isolated lives experienced by those who work in them. Tucked away in a corner of the south east, Folkestone isn't really on the way to anywhere except France and, watching Sedira's films in a space cut into the cliff, it feels like you're detached from the rest of the world, on an island even, protected from the waves that crash against the rocks on screen. It's hard to forget that Calais is 30 miles from Folkestone – less than half the distance to London, and a number of works dwell on themes of immigration, displacement and cultural alienation. These include a floor of office space in the high street given over to an installation by Israeli artist Smadar Dreyfus, where visitors stumble around different rooms, filled with the sounds of children's classrooms. The total darkness and unfamiliarity mean it's completely disorientating.
Right at the Western end of the Leas is what looks, if you notice it at all, like an unusually large piece of topiary. Hidden below a gently swaying mass of leaves is a Martello tower, one of many solid, round structures that were built to defend the coast against Napoleonic attack. They still stand along the Kent coast in various states of repair, from crumbled ruins to now-desirable house conversions. This Martello tower is so deserted it has gone beyond a ruin to a jungle, and Spanish artist Cristina Iglesias has cut a wavy path up to it through the undergrowth. With leaves above your head, and the foliage multiplied by mirrors and castings of branches, it's like you're walking into a hedge. You emerge into a viewing platform, separated from the Martello tower by a living moat of brambles and nettles, to admire the tower. It might be hidden, but it's still standing after centuries in front of the ancient Kent hills.
The tower's nearest neighbours are mansions overlooking the sea set in spacious, sun-catching grounds. On the same stretch, and slightly further towards the town, is the massive Grand Hotel. With vintage open-top Jaguars parked outside and afternoon tea served to live music on a grand piano, it's one of the few places where it's possible to imagine how glamorous Folkestone would once have been. Yet Brazilian artist Tonico Lemos Auad leads you through the vast, spacious rooms with plush carpets and elaborate wallpaper to a plain back-room with floorboards and old furniture – a part of the hotel that isn't normally seen by visitors. It houses a giant scratchcard which visitors are invited to scrape to reveal images of seaside festivals, from Brazilian carnivals to Folkestone's annual Charivari parade. Auad has also placed work in another sometimes hidden space, down at the harbour – low tide reveals Carrancas, carved figureheads inspired by Brazilian good-luck talismans, attached to poles amongst the boats that have come to rest on the (usually submerged) harbour mud.
At the nearby Harbour station, the train tracks snake right out into the sea on a pier for trains to be loaded onto boats. A sculpture by Paloma Varga Weisz has landed on the tracks, on top of what could be a magic carpet – only it's been grounded and Folkestone's its final destination. The figures on the rug are going nowhere, and neither is anyone else – the station was closed in 2009. The station and pier are decrepit, but have spectacular views over the sea to the White Cliffs of Dover, where cross-channel traffic continues.
By the sea a bell, removed from a church because it no longer fits the tuning of the other bells, is suspended over wasteland, waiting for passers-by to ring it. The surrounding area is also in suspense – once home to the Rotunda fun fair, source of memories of childhood birthday parties and, when we were older, Friday night trips to the rides, it was cleared for redevelopment (a supermarket, casino, leisure complex and housing were all suggested for the site), before the recession and a tussle over opposing plans for the land put development on hold.
The other side of the Harbour, at Sunny Sands, the town's sandy beach, I was sceptical about seeing Cornelia Parker's mermaid sculpture, thinking I wouldn't find much of interest in a sculpture copied from an iconic artwork so associated with another place. In real life though the figure, cast from a local woman, is rather lovely – she stares out to sea, calm and serene on a rock above the crowded chaos of beachgoers with their personal stereos, livid skin and screaming children.
Back up the cliff, in the town, Hew Locke has placed colourfully painted wooden boats on a bright sea of lightbulbs in secluded St Eanswythe's Church. Hanging below the wooden beams of the roof (you realise the nave of the church itself is shaped like an upturned boat), and above antique wooden pews, the boats make you notice the beauty of the friezes and stained glass windows that are already there.
One sign of the town's changing fortunes is the restoration and reopening of the Leas Lift, a Victorian water lift. £1 gets you up or down the cliff – soundtracked by an installation by Martin Creed. I took the Lift up the cliff, and the ascent is matched by a musical composition performed by local string players. It rises like a musical scale, starting off with a low grinding and ending in a high pitch, in a reassuringly smooth transition as the lift stutters and clacks its way towards the Leas.
Other highlights of the festival include Spencer Finch's giant colour wheel and flags, changed daily to match the colour of the sea. Strange Cargo, who have long been doing good projects in the town, complement the Triennial's artworks with plaques drawing your attention to the quirkier aspects of the town's history, drawn from the memories of local people. Perhaps best of all, though, are Ruth Ewan's subtle interventions into the town's timing. She has placed clocks in prominent (and some not so prominent) places in the town, from a pub to a fireplace in the woodlined bar of the Grand Hotel, next to important-looking portraits, to the former town hall and even an entirely new clock on the Leas. The clocks have been changed to French republican time – meaning they only go up to ten, making you do a double take and look again more closely!
It's not often enough you get to be a tourist in your home town. It's three years since I last spent any significant amount of time in the area, but Folkestone's transformation from the place where I grew up has been considerable with new bars, cafes, galleries, independent businesses and venues, and even a University College Folkestone. The Triennial seems to be having a knock-on effect, with its own fringe festival this year – something to explore next time I visit!
Folkestone Triennial is free and runs until September 25.