HIS architectural masterpieces, such as Glasgow School of Art, are known around the world and celebrated by the likes of Brad Pitt and Barbra Streisand.

Indeed, so synonymous with the city of his birth is Charles Rennie Mackintosh that Glaswegians may assume they already know all there is to know about the architect, designer and artist’s work.

They’d be wrong, though. Even aficionados are likely to be unfamiliar with some of his lesser known works, the hidden gems - from gravestones to a telephone kiosk – that pop up in sometimes the most unexpected city locations.

All are easy to find if you know where to look. And with this in mind I set out on a walking tour with Stuart Robertson, director of the Charles Rennie Mackintosh Society, which just happens to be based at the first hidden gem to tick off our list.

Queens Cross Church, 870 Garscube Road, Glasgow, 1896-98.

People come here from all over the world to see Mackintosh’s only church, but many locals still walk past this building in Maryhill, unaware of its architectural or cultural significance. As well as being home to the Society, in 2006 it received a £1m refurbishment and this stunning space now hosts gigs and events throughout the year.

“This is the first building Mackintosh had complete control of and you can really chart his development as both an architect and designer,” says Robertson. “He designed everything, inside and out.”

“It’s a very peaceful, tranquil place, a real oasis just 15 minutes from the city centre. Internally, you can see Mackintosh’s burgeoning interest in Japanese art, which he developed more fully at Glasgow School of Art, while externally you see the influence of the Scottish and gothic traditions.

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“What I love most are the subtle details in the stonework and wood carvings. He doesn’t explain them – he leaves it to you to enjoy and add your own interpretation of meaning. Kids absolutely love it here. We have a project called Design Detectives where they find all the hidden symbols, which is great fun.

“Musicians also have a very profound, often spiritual reaction to playing in the church – it is a truly magical place. And yet so many people don’t know it is here.”

Museum of the Moon, a huge art installation accompanied by a programme of musical events, runs at Queens Cross Church until 24 June.

Martyrs School, Parson Street, Glasgow. 1895-98

Few drivers who come off the M8 slip road at the Glasgow Royal Infirmary on their way into the city centre realise they are passing one of the earliest buildings by one of the world’s most revered architects. But that’s exactly what Martyrs is.

The sandstone school is just a short hop across a footbridge from the hospital in the Townhead district of the city, and was built in the very street where Mackintosh was born (in 1868) and would have played as a child.

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Commissioned by the School Board of Glasgow, the building shows early indicators of the style Mackintosh, then employed by architects Honeyman and Keppie, would later develop and perfect. Despite its significance, the structure remains largely unknown (unlike the other school he designed, at Scotland Street in Tradeston) and is currently used as a resource centre for social workers. It’s not open to the public but there is much to enjoy even from outside.

“Mackintosh may have asked specifically to be involved in this project,” says Robertson. “He would have known these streets well.

“It’s a relatively plain building both inside and out, but it is extremely impressive, especially since Mackintosh was only in his twenties when he worked on the design.

“Inside, it is planned around a central light well, but the exposed roof timbers are very unusual, a definite Mackintosh touch. He plays with this roof light and we can see perhaps the first signs of the Japanese influence which he later took to Queens Cross and Glasgow School of Art.

“What I love most about this building is Mackintosh’s awareness that children would spend time here and his wish to making it an inspiring place to learn. It’s the same at Scotland Street. You can imagine the children running up and down the stairs – indeed you can still see the small feet on the worn steps.”

READ MORE: Vote for your favourite free Mackintosh print

Gravestone, Glasgow Necropolis, 1888.

With its stunning views across the city, the Necropolis, which overlooks Glasgow Cathedral and the Royal Infirmary, has long been a popular spot for city dwellers seeking a moment of tranquillity and reflection. But few of those walking amid the gravestones and mausoleums commemorating the great and the good of the city know that one of them was designed by Mackintosh.

Half way up a path on the east side of the cemetery stands the grave of Alexander McCall (1836-1888), a police officer who served as chief constable in Glasgow for 18 years. Mackintosh’s father, William, worked as his civilian assistant and it is thought he asked his son, then in his early twenties, to design the memorial gravestone.

“The main element of the gravestone is a granite Celtic cross which is indistinguishable from numerous others found in Victorian cemeteries all over Scotland,” says Robertson.

“At the bottom there is a bronze tablet with an inscription and portrait, the original of which is currently on show at the Mackintosh exhibition at Kelvingrove Art Gallery and Museum. And although there are few strong hints of Mackintosh’s future style, the beautiful Celtic knot design has a definite art nouveau feel.

“This is a true hidden gem – hardly anyone knows this was designed by Mackintosh, especially as it small and quite unassuming in comparison to some of the grander designs in the Necropolis. But it’s really worth seeking out.”

Lady Artists Club, 1908

The elegant neo-classical terraces of Blythswood Square have many impressive doorways. None more so than the unusual and stunning entrance at No. 5, which was designed by Mackintosh.

Commissioned by The Glasgow Lady Artists’ Society to design a new doorway and redecorate the hall and staircase of their club, Mackintosh didn’t disappoint, producing an elegant black entrance that remains in beautiful condition. Now an upmarket office, few of the suits who pass by every day know the history of this doorway. Inside, tucked under the stairs, meanwhile (but not open to the public) is a stained wood telephone kiosk.

“Dating from just after the opening of Glasgow School of Art, which is only a few streets away, this is another hidden wonder,” says Roberston. “The tops of the pilasters are decorated with carved organic shapes set into the flutes, reminiscent of Queens Cross Church and the library at the art school, which is currently being rebuilt following the fire. The Japanese influence is very much in evidence.

“This particular doorway is even more interesting because the design was very controversial at the time. It is also just round corner from Mackintosh’s first marital home.

READ MORE: Why Mackintosh still matters

“Mackintosh’s influence on Glasgow is profound. And yet there are still so many pieces and places for people to discover him, so many hidden gems for people to seek out in Glasgow and beyond.”

There’s still time to vote for your favourite free Mackintosh print, which will be given away with the paper on June 7. Go to www.heraldscotland.com for details.

For information on guided tours run by the Charles Rennie Mackintosh Society go to www.crmsociety.com.

Charles Rennie Mackintosh: Making the Glasgow Style is on at Kelvingrove Art Gallery and Museum until 14 August.