A concert has been held at the Big Pit National Coal Museum in Blaenavon in memory of those who have lost their lives in coal mines.
It took place 300ft underground, with an upright piano also making the descent - possibly for the first time in history.
First Minister Carwyn Jones was among those present.
The concert comes two days before the first anniversary of the Gleision Colliery disaster.
David Powell, Garry Jenkins, Charles Breslin and Phillip Hill died when the mine they were working in flooded on September 15 last year.
The concert had been organised by Daniel Curtis, whose great-grandfather was one of over 400 who died in the 1913 Senghenydd Colliery disaster.
Daniel, who himself performed at the concert, decided on a musical tribute as singing was an important part of mining history, with many miners members of their local male voice choir.
He says his dream of holding a tribute concert underground has finally been realised.
I contacted Big Pit with my fingers crossed that they wouldn't think I was crazy! I really wanted to hold a concert to pay tribute to, and raise awareness for, those who have died in mines. The number of people who lost their lives through the years is one of the biggest tragedies running through the history of Wales and Britain.
Big Pit's mine manager Peter Walker says he was only too happy to agree to Daniel's request.
We feel passionately that any effort to keep the memories of this most important industry alive is vitally important. We have had many weird and wondeful events underground!