The 40th anniversary of the opening of a 17th Century stately home to visitors will be marked by National Trust Wales.
A new audio-visual exhibition will chart the story of how Philip Yorke III, the last squire of Wrexham’s Erddig Hall, gifted it to the charity after it fell into disrepair.
It took a four-year, £1m restoration to get the house and gardens back to their former glory.
It now costs the National Trust £81,000 a month to run it.
Mr Yorke’s family had lived at Erddig Hall since the 1700s but by 1973, large parts of the 70-room house were in urgent need of repair.
He had lived out of one room for seven years, trying alone to combat the decay, with no heir nor family to help him.
Mining directly under the house after World War Two caused the building to drop 5ft (1.5m) on one side.
The roof was rotten and leaking, causing damage to hand-painted wallpapers, and the family’s collection of 30,000 paintings, furniture, ornaments and trinkets was disintegrating.
Finally, Mr Yorke took the difficult decision to hand over the house, grounds and all its contents to the charity.
He died in 1978 – one year after the house opened its doors to the public. At the time, he said: “I rather like the idea of people coming to see [the house].
“[When I was young] it was very well run and we had lots of people staying here in the summer. They [the National Trust] are going to do it up so people can come and enjoy it as it used to be.”
Jamie Watson, Erddig’s general manager, said: “It is not just the monetary cost of looking after a home of this size – a lot of time and care goes into making sure the rooms, 30,000-plus ornaments and furnishings and 1,200 acres (485 hectares) of parkland and gardens are maintained for future generations.
“Unfortunately, it came to a point for Philip when he was no longer able to do that, but we are very lucky to have our team and generosity of our volunteers to help keep his memory alive and protect his home and everything in it, just as he wished.”