One man has marked the centenary of the Senghenydd mining disaster in a special tattoo. It reads: "14th October 1913 In Memory of 439 Lost".
He told ITV News it took 6 hours to complete.
Bill Richards was at the scene of the Cambrian mining disaster in Clydach Vale in 1965, in which 31 miners were killed.
Here, he talks to ITV News about his memories of the disaster.
Today marks the centenary of the UK's worst mining disasterRead the full story ›
A group of schoolchildren released black balloons this morning to commemorate the 100-year anniversary of the Senghenydd mining disaster.
The balloons were a tribute to the 439 miners killed in the Universal Colliery at Senghenydd in 1913.
Just heard the hooter go off at 8.10am like it did 100 years ago 439 miners lost their lives in the biggest pit disaster ??
The sound of the original Universal Colliery Pit hooter has rung out across the Aber Valley this morning.
It's to remember the 439 miners who died at Senghenydd, Britain's worst mining disaster, 100 years ago today.
Follow @Senghenydd1913 for real-time updates of the explosion.
All 950 men of the day shift are now underground. The Banksman & winders turn their attention to bringing up coal & sending down supplies
The sound of a terrific explosion echoes down the Aber Valley
Alerted by the explosion, crowds begin to gather at the pithead waiting for news & to offer assistance
The organisers of the Wales National Mining Memorial are tweeting real-time updates of the Senghenydd mining disaster.
An explosion killed 439 miners and one rescue worker on 14 October 1913.
Events to mark the centenary are taking place at Senghenydd today including an unveiling of a national memorial to remember all victims of mining disasters in Wales.
Wayne Thomas is the South Wales General Secretary for the National Union of Mineworkers.
He said it is "wonderful that there is a National Mining Memorial being erected in Wales - at last."
"It is really important to remember where we have come from."
Both Hilary Barbrook's grandfathers were killed in the explosion at the Universal Colliery in Senghenydd on 14 October 1913.