Four people died following fatal collision minutes in Brecon Beacons . One of the victims was grandmother Margaret Elizabeth Challis , 68 . Three 17-year-old teenagers from Barry , South Wales , also died in crash . Further three people were injured and are in 'serious condition ' in hospital . Five teenagers have been arrested on suspicion of dangerous driving . Hundreds of people have taken to social media to pay tribute to victims .
Four people died following fatal collision last night in Brecon Beacons . One of the victims was grandmother Margaret Elizabeth Challis , 68 . Three 17-year-old teenagers from Barry , South Wales , also died in crash . Further three people were injured and are in 'serious condition ' in hospital . Five teenagers have been arrested on suspicion of dangerous driving . Hundreds of people have taken to social media to pay tribute to victims .