According to the song, no-one know 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 (September 7 and 8).
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 locally are part of a programme co-ordinated by North Lanarkshire 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.
St Andrew’s United Free Church in Bellshill will be open on Saturday from noon to 4pm and Sunday from 11am to 4pm.
Tours of the church and literature on its history will be available. A car treasure hunt will take place on Saturday at 1pm, with teas and coffees available.
Please note, the Sunday service is 11am to 12.30pm.
Lanarkshire Central Mosque in Mossend will be open on both Saturday and Sunday from 10am to 5pm.
Activities include a tour of the mosque and an opportunity to find out more about Islam.
Group tours can be arranged by contacting Ghulam Siddiquie on 07946 366652 or 01698 730650.
Dalziel St Andrew’s Parish Church in Motherwell will be also open on Sunday from 11am to 4pm.
Take a tour of the church and find out about its history.
Sunday Service is at 11am, with teas and coffees available in the church hall after worship.
Lanarkshire Family History Society in Merry Street, Motherwell, will be open on Saturday and Sunday from 11am to 3pm.
There will be continuous tours of the research centre facilities. Members will be on hand to advise on starting your family tree.
Children under the age of 16 must be accompanied by an adult. Further information can be found at www.lanarkshirefhs.org.uk.
Motherwell Community Fire Station will also open on Saturday and Sunday from 11am to 3pm.
Find out more about the work of firefighters, with a rare chance to sit in a fire engine and take a tour of the station.
Community safety advice will also be provided.
However, visitors should remember this is a working fire station and fire engines may be unavailable at times.
North Lanarkshire Heritage Centre in Motherwell will be open on Saturday from 9.30am to 4.30pm.
There will be a Bookbug session for children aged 0-4 from 10.30am to 11am.
There will be family-friendly, behind-the-scenes tours of the archives, local studies and object stores at 1pm, 2pm and 3pm.
And there’s a walk and talk with New York-born photographer Larry Herman about his new exhibition, Clydeside 1974-1976, at 2pm.
From 12.30pm to 3.30pm there will be a range of gamily activities including Back to the 80s featuring objects and memorabilia from the 1980s such as tape cassettes, electronics, comics, toys and videos, plus 1980s badge making (£2).
A key event sponsor neatly identified why Doors Open Days is such a success ... it’s all down to the simple desire to see something which is 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.”
Thomas Knowles, head of grants at Historic Environment Scotland, added: “We’re proud to support the annual initiative as it ticks all the right boxes for projects we consider for grant funding.
“It shares our values to promote public access to the historic environment, but it also delivers benefits like driving visitation to, and developing knowledge about, properties and places not open year-round.”