The development of the 'bouncing bomb' used in the Dambusters raid by the RAF on Nazi Germany 70 years ago has it roots in a remote corner of Wales. The Nant y Gro dam on the Elan Valley Estate near Rhayader was blown up in a series of experiments overseen by Sir Barnes Wallis.
As a result he realised the only way to destroy such structures was to develop a bomb that rotated so that it would roll down the wall of the dam to its base.The bouncing bombs were used by the RAF's 617 Squadron in 1943 to breach two dams in the industrial area of the Ruhr Valley in Germany.
The resulting flooding and destruction was a sizeable blow to the Nazi war effort. The Nant y Gro was built by the Victorians to supply water to the workforce building the reservoir and other dams in the area.
When it was destroyed in the RAF experiments it had reached the end of its working life but its wartime role stayed secret for many years. However the ruins have now been cleared and it's hoped they will attract visitors to the area which is already popular with tourists.
The television series that documents Prince William's time with the Search and Rescue operations coincides with the news that the service is to be taken away from the RAF and privatised - a move that the prince is believed to have opposed.
BBC One Wales have released a short preview video for Helicopter Rescue, the documentary featuring Prince William and the Search and Rescue team at the prince's base at RAF Valley on Anglesey.
The Duke of Cambridge is shown piloting a helicopter on a rescue mission to a slate quarry in Blaenau Ffestiniog.
One of his crew are winched from the ground after rescuing a boy who had fallen off an old railway bridge onto rocks.
"As captain you're trying to play out the entire rescue, the transit to the rescue and back again in your mind, and pick up any circumstances or problems you can foresee, and try and fix them on the ground before you get airborne," he says in the programme.
After winning the contract to take over search and rescue helicopter cover from the RAF, Bristow Helicopters have released details of the new fleet that will be deployed in April 2015.
There will be two helicopters at both its Welsh bases -Caernarfon Airport and the MOD site at St Athan near Barry.
Caernarfon's Sikorsky helicopters will cover an area of 250 nautical miles around the base and each carry three stretchers and up to 10 seated casualties. Augusta Westlands will cover 200 nautical miles around St Athan and each have room for two stretchers and six seated casualties.
All the helicopters will have a crew of four and be capable of flying at 145 nautical miles an hour.
The Department for Transport has said that under the new contract helicopters will be able to reach a larger area of the UK Search and Rescue region within an hour of take-off than is currently possible.
It added that, based on historic incident data, it is estimated there will be an overall improvement in flying times to incidents of around 20 percent (from 23 to 19 minutes).
Presently, approximately 70 percent of high and very high-risk areas within the UK SAR region are reachable by helicopter within 30 minutes. Under the new contract, approximately 85 percent of the same area would be reached within this time frame.