Inside the crater are two boiling pits of water with the biggest pit boiling so vigorously that it ejects hot water about a metre into the air.
It's pretty interesting stuff.
The journey from the main road to the crater should be undertaken on foot due to the terrible condition of the road, but cars and bikes can make it to the top, albeit very slowly and at the expense of shock absorbers, a sore bum and a real risk of damage to the vehicle. From the main road it is a kilometre to the crater.
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