The big disappointment of the trip was that Ijen Crater, an active volcano, erupted the day I arrived, spilling toxic gas that sickened 30 people and killed the flora along an entire riverside. (Thanks to Wikipedia, I can at least put in some images…sigh.)
It remained closed the duration of my stay, so I had to forgo the awesome experience of seeing blue fire belching out of a sulfur-laden hillside.
Next time.