Eternal flame: How Azerbaijan became the 'Land of Fire'
https://edition.cnn.com/travel/article/yanar-dag-azerbaijan-land-of-fire/index.html
When it comes to most of the ordinary tourist destinations, there is basically nothing to endanger lives of the tourists. But, in Yanar Dag, eternally burning rock can spread fire on clothes of tourists. So, there should be safety countermeasures for them.
