Glasgow always surprises you. Just when you think you know something about the city, you discover the truth is somewhat different. Take the vast pipe organ at Kelvingrove Art Gallery which dominates the main hall. Often I have stood staring up at the pipes, that look like golden spears threatening to rain down on you, topped with trumpet-playing cherubs, marvelling at the sound they produce. Only they don't. The pipes and walnut front of the organ are just for show. The 2889 pipes that actually produce the sound are out of sight behind the facade.

But what a sound it is. Visitors to the museum and art gallery on Sunday were treated to the 3000th daily organ recital at Kelvingrove which is a world record for daily recitals. Jim Hunter, director of music at Kelvingrove, and the man in charge of the programme, tells me why the recitals are held every day specifically at 1pm - it's because of Edinburgh. Says Jim: "Lord Macfarlane, who initially raised the money for the recitals years ago, wanted them at the same time as the One O'clock Gun goes off at Edinburgh. That way he could tell people that if you want to hear a gun being fired, go to Edinburgh. However if you want culture, then go to Glasgow." The only concession is that on Sundays it's at 3pm.

Lord Macfarlane jokingly refers to himself as one of the "Golden Oldies" - successful business people such as himself, Boyd Tunnock of caramel wafer fame, car seller Arnold Clark, and property developer Billy Mann who initially came up with the cash for the programme, although new sponsors are being sought. It is important that the recitals are free. If it was a paid-for concert then it would put off people who can just casually drop in at Kelvingrove and hear the music.

So while there are people sitting down intently listening, mothers with squeaky buggies can stroll past. One mum with her baby in a papoose on her chest starts dancing to the organ music while holding her little tot's hands. This is not a sound you can ignore. The music seems to roar out of the stone walls, reverberate off the marble floor and soar to the vaulted ceiling high above you, almost as if you yourself are standing inside a giant instrument. The organist looks like a toy figure, perched on his bench behind a balcony on the first floor. But two television screens have been added below the organist which show close-up pictures of his hands on the keyboards and his feet on the pedals. The feet dance across the wooden pedals as if they were burning hot and have to move constantly.

One memorable occasion was when Carol Williams, city organist of San Diego asked to play. Jim Hunter had to explain that they couldn't afford her, but such is the reputation of the Kelvingrove organ that she happily accepted the modest fee on offer. Wearing pink ballet shoes she captivated her audience with her memorable rendition of the Flight of the Bumblebee. Being Glasgow, the crowd shouted for numerous encores which she was happy to play.

The organist from the White House in Washington came to play once. "No' a bad player," one of the museum staff remarked to Jim after the recital, not knowing who the player was. "I'll let the president of the United States know," Jim replied.

A sadder note was struck last month when a blind organist from Christchurch Cathedral in New Zealand asked if he could play the organ, built by famous organ builder TC Lewis in 1901. Christchurch Cathedral used to have the largest Lewis organ in the world but it was destroyed with the cathedral in New Zealand's terrible earthquake. The organist was taken up to the keyboard and once the set-up was explained to him, his face shone with joy as he once again played at a Lewis organ.

Kelvingrove though is not a cathedral. Thus the organ is not restricted to the solemn music of a religious nature. Sunday's concert ended with Tchaikovsky's 1812 overture, complete with recordings of cannon fire. Just this once you could hear a gun being fired in Glasgow alongside the culture.

Some organists have been experimental. Chris Nickol, staff pianist at the Royal Conservatoire in Glasgow, might seem like a quietly-spoken classicist, but he performed rock hit Highway to Hell by AC/DC on the Kelvingrove organ at one recital. Sunday's performance included hits from the Sound of Music which had gallery visitors singing along.

The Friday concerts are also a bit special as Jim Hunter will take folk on a tour of the organ after the recital. It is still in its original condition. Jim almost purrs as he tells me it has three manuals and pedal console with 48 speaking stops controlling the nearly 3000 pipes. I nod approvingly although I have no idea what he is talking about. Let's just say that this is a complex instrument, a mechanical miracle, and it is amazing that it has been preserved all these years, and truly is one of the musical wonders of the world. And it is right here in Glasgow.

A delighted Archie Graham, chair of Glasgow Life, the organisation that runs Glasgow's museums, tells me: "A new world record of 3000 concerts is an outstanding achievement and truly worthy of recognition. Since Kelvingrove re-opened in 2006, the sound of the much loved pipe organ has been enjoyed by many thousands of visitors from around the world."

Mind you, Jim Hunter tells me he was stopped after he gave one of the recitals by a regular attendee who said accusingly: "Did you not play that piece about five months ago?" Even when it is glorious, soaring organ music which makes all your senses soar with it, you still have to work hard to completely please a Glasgow audience.