According to the song, no-one knows what goes on behind closed doors.
But for one weekend every year, visitors get the chance to see key sites through new eyes as hidden facets are finally revealed.
Doors Open Days is taking place across North Lanarkshire this weekend (Saturday, September 8 and 9).
Billed as Scotland’s largest annual celebration of the built environment, it has the backing of Historic Environment Scotland, European Heritage Days and the Scottish Civic Trust.
Yet the varied venues involved in Cumbernauld, Kilsyth and beyond are part of a programme put together by Cumbernauld man Adam Smith.
North Lanarkshire Council used to do the honours but budgetary concerns meant it could not continue wholesale.
So Adam stepped in and has co-ordinated a range of must see properties, right here on our doorstep but seldom fully seen.
The doors will remain closed on the cutting-edge penthouses atop Cumbernauld Centre and the Barr’s factory but there’s plenty to see this year.
Adam, who lives in Kildrum, said: “We have ten participating venues in Cumbernauld and Kilsyth alone, with some fantastic first-time additions.
“While we’re unable to offer some old favourites such as the penthouses, I’m delighted that we’ve added to the programme Cumbernauld Academy, Freedom City Church Centre, Broadwood’s gym and Kilsyth Fire Station.
“We also have some buildings which are opening their doors to the public for the first time since 2015.
“Available activities include an exhibition of old pictures of Cumbernauld at Freedom City Church Centre and screenings of old movie clips of the town at Cumbernauld Museum.
“We will also have access to emergency service vehicles at Cumbernauld and Kilsyth Fire Stations and there are backstage tours at Cumbernauld Theatre.
“There is, of course, fantastic history and great architecture at Cumbernauld Old Parish Church and at St Patrick’s and Burns and Old Parish Churches in Kilsyth.
“I’m also delighted that this year Stagecoach has again agreed to provide a free shuttle bus to take people around the participating venues in Cumbernauld.
“I hope that as many local people as possible will make use of this service and will take part in this year’s Doors Open Days programme within North Lanarkshire.”
That view was very much backed up by the other organisations involved in the ambitious event, which is rolled out in September across Scotland.
Susan O’Connor, director of the Scottish Civic Trust, said: “Doors Open Days is a fantastic opportunity for communities up and down the country to show off the best of their buildings. We’re thrilled with the range of architectural wonders on display this year and we can’t wait for people to enjoy as many sites as possible.”
Thomas Knowles, Head of Grants at Historic Environment Scotland, said: “Historic Environment Scotland is proud to support the annual Doors Open Days initiative as it ticks all the right boxes for projects we consider for grant funding.
“Not only does the initiative share our values to promote public access to the historic environment, but it also delivers benefits for communities like driving visitation to, and developing knowledge about, properties and places not open year-round.”
Meanwhile, a key sponsor neatly identified why the event is such a success with such a broad cross section of people.
And that’s down quite simply to the simple desire to see something that’s normally hidden away from view.
Claire Drummond, head of charitable giving at Aberdeen Standard Investments, said: “Doors Open Days satisfies the curiosity – and dare I say the nosiness – in all of us!
“What lurks behind the doors that we pass every day? What fascinating history does that building hold?
“How does the work done behind those doors support our everyday living?
“Being a free event, it’s an excellent opportunity for families to explore what’s on their own doorsteps.
“We would like to wish the event every success.”
For a complete-run-down of the programme in Cumbernauld, Kilsyth and across Scotland, visit www.doorsopendays.org.uk.
Contrasting sites of interest
Two places of worship on the list share a connection despite being in different towns. Sacred Heart Parish Church in Kildrum and St Patrick’s in Kilsyth were constructed by the same cutting edge-firm of Glasgow architects, Gillespie Kidd and Coia, in the 1960s.
Each church, however, has surprisingly different styles with the Kilsyth creation being more simple than the more elaborate Sacred Heart.
Those who prefer more traditional buildings have a greater contrast still with Cumbernauld Old Parish Church. The existing building dates back to 1650 in its earliest form. A north aisle was added in 1959 which allowed for a pulpit in the middle of the south wall which could be seen in all sections of the kirk – an arrangement which is still in place today. The building would be further enlarged in the 18th century and the rest is history.
Time is running out to see the surprisingly complex layout of Cumbernauld Theatre, much of which lies below ground level.
The theatre is set to close and will be incorporated into the new campus of Cumbernauld Academy. While this is no longer expected to happen next year, there is no guarantee the historical premises will be able to take part next year.
Former pupils of Cumbernauld Academy can, of course, enjoy what will likely be the last chance to saunter down memory lane, given that the decades-old secondary is now on the list.
Transport buffs are always drawn to Glencryan bus garage, Stagecoach’s West Scotland headquarters.
The Perth-based company is continuing to provide free transport for visitors during the Doors Open Days festival as a goodwill gesture to the town and its people.