🇮🇩Ijen volcano, Indonesia

Ijen is an active volcano in Indonesia, to the crater of which you can make fascinating excursions. 

Picturesque trails lead to the mouth, along which tourists get to the edge of a natural spring, amazing in its appearance and content

During the tour, tourists can also visit coffee and tea plantations, get acquainted with the living and working conditions of local residents
https://earth.google.com/web/search/Ijen