It is well-known as the river that gave Belfast its name and High Street its curving shape. Northern Ireland's capital city was founded at a settlement centred on a muddy ford over the River Farset, close to a sandbank where it joined the River Lagan.
Old drawings show a bustling river which powered Belfast's industrial development and ferried traders into what is now High Street.
But most locals would be hard-pressed to pinpoint exactly where the Farset flows before it reaches the city centre – because almost the entire route is now hidden beneath our feet in the form of culverts.
The Greater Shankill Partnership recently revealed it wants to transform one of the few open stretches of the Farset into a public amenity as part of its long-term Shankill Greenway plan.
And this week we turned detective to trace the river from its source to the point where it spills out into the Lagan.
According to the Belfast Hills Partnership, the source of the Farset is to be found just above the Horseshoe Bend, where the Crumlin Road turns into Ballyutoag Road.
Local resident Joe McAdam showed us the exact spot where the river rises from a bed of watercress and nettles in a field yellow with ragwort and flickering with white butterflies.
Horses graze in the field high above the city, and can be seen dipping their noses deep into the watercress bed as they search for a refreshing drink of water. The stream merges with another that rises in a hedge nearby before plunging beneath the Ballyutoag Road and through a tree-cloaked gully into the fields below.
Joe, who grew up there, said the watercress is edible.
"It's lovely in a salad," he said. "I had this whole hill as a playground when I was growing up."
The Farset next emerges on the other side of the fields, pouring through brambles into a litter-strewn grille beneath the Crumlin Road and down into Ballysillan.
From there, it flows behind a short row of shops at the top of the Oldpark Road. The small river tumbles over stones before rushing deep into a tunnel beneath the Happy Choice Chinese takeaway.
Zoe Ferguson, who works at the neighbouring Zoe Alexander Hair and Beauty shop, said she knew a river ran down the back but had no idea it was the Farset.
After this, the river races through a series of culverts, reappearing for short stretches within Ballysillan Park. One stretch runs along a path frequented by dog walkers off Deerpark Road but is caged by steel fencing and grilles before disappearing underground into culverts running under Alliance Avenue, parallel to Jamaica Street and down Flax Street.
A number of other small waterways are culverted into the main River Farset on this stretch.
The next part of the route can be traced by the old mills that once relied heavily on the Farset's water. The river is then culverted along the side of the old Brookfield Mill, cuts across the car park at Hillview Retail Park and emerges into the open air along a short, straight channel edging Edenderry Loft, also a former mill.
According to Shankill tour guide Jake Kane, the period houses along Tennent Street parallel to the watercourse were originally built to house mill employees.
The river then vanishes back underground at Sidney Street West, disappearing under an area of waste ground before skirting Tennent Street PSNI station and emerging from the archway above the old Shankill Graveyard.
Jake told a story about a friend who clambered in through the archway to find out where the tunnel would take him.
"He walked from the river just at the Shankill Graveyard archway and came out at Sidney Street West. That was in 1970, before there was as much security – you couldn't do it today," he said.
He described throwing bricks at the rats along the river when he was a boy and diving into dense vegetation that bounced back up.
Once, when he threw a ball out of the grounds of Glenwood Primary School, he found a steel pole poking out of the ground when he was searching for it. When he investigated he found an old pigeon hut and a concrete structure with a door.
"When I opened the door, I walked down the concrete steps and it was a bunker from the Second World War," he said. This stretch of the river resembles an open drain, hidden away behind high walls and metal fencing, but is dense with pink flowering Himalayan balsam.
The Greater Shankill Partnership is keen to open it up to the public, adding a circular path that will take in both banks and lead back into the historic graveyard.
The rushing water can be heard by children in the playground at Glenwood Primary and at the rear of the Co-Op funeral home.
Pigeons can be seen rising into the sky from the Bootle Street pigeon club, where fanciers' huts sit along the side of the waterway.
From here, the Farset disappears under a bridge beneath the Shankill Road and flows through a culvert beneath Lanark Way. Before the road was built, it was known locally as the Meadows and was home to scrapyards.
The culvert continues south beneath Battenberg Street then veers left, running parallel to Cupar Way and under Ashmore Place. A number of culverted tributaries join the Farset at this point before it continues parallel to the peace wall at Beverley Street and then on beneath Finn Square and Fingal's Court before emerging very briefly into the open air.
At this point the river is visible to tenants of Townsend Street Industrial Park, who can look out over a broad concrete channel where the waterway splits in two. A yellow wagtail touched down briefly on the railing over the moss-covered concrete bank of the channel, which Rivers Agency director of engineering Pat Aldridge said is checked weekly.
Here, one fork leads off to the Blackstaff system before discharging into the Lagan at the Gasworks, while the other broadly continues along the original Farset route.
"We had the opportunity in the 1980s to undertake a major upgrade of the Blackstaff River and create extra capacity. As part of that, there was a connection made and an overflow facility provided from Townsend Street to drive water into the Blackstaff," Mr Aldridge said.
The Farset culvert now turns sharp left, runs beneath the peace wall along Townsend Street and then crosses the Westlink before turning right again and then veering underneath Belfast Metropolitan College at Millfield, in order to avoid the deeper section of the Westlink.
It then cuts underneath a corner of the multi-storey car park opposite the college, round beneath the buildings beyond and continues under Bank Square and along Bank Lane before navigating the length of High Street.
It's thought the traditional entries off High Street once lined up with bridges that crossed the River Farset centuries ago when it was a busy quayside at the start of Belfast's emergence as a merchant city.
Finally, the river skirts round the left hand side of the Albert Clock, runs under Custom House Square and spills into the Lagan underneath the Big Fish.