An 80-metre wind turbine has collapsed on a mountainside near Fintona in County Tyrone.
The turbine was one of eight on the Screggagh wind farm on Murley mountain.
It is not clear what caused the giant structure to collapse, but people in the industry said it was a highly unusual event especially as winds were light at the time.
The turbine, valued at over £500,000, collapsed on Friday evening, scattering debris over a wide area.
People in the area said the rotor blades were spinning out of control on the evening the turbine buckled.
The sound of the failing mechanical structure was heard more than seven miles away.
Some people said the sound was like thunder. Others report grinding and the sound of metal against metal.
There are no reported injuries.
Debris from the stricken turbine is scattered across the mountainside and a large spike remains impaled in the earth several hundred yards from the turbine site.
The turbine is one of eight on Screggagh farm which was commissioned in April 2011.
The site operators have fenced off the site and and are investigating the cause of the collapse.
The turbine collapsed on Friday evening, scattering debris over a wide area
The turbine is one of eight on Screggagh farm