On the way to Caerleon, as we had time to spare, we managed to fit in a short walk on these reclaimed coal tips near The Big Pit.
The sun was hot, the air was still and I heard an irregular popping sound. The sound was not very loud, but very distinct. Standing motionless, I eventually tracked it to some bushes and closer inspection revealed that it was caused by seed pods bursting. I made a short video in an attempt to capture this strange phenomenon. A bit of Googling suggests that the bush in question was common broom.
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