Allar Cave is one of the few named natural sights close to Yardimli, set in the hills west of town. It is a small-scale stop, but a worthwhile one if you are already exploring the district by car.
Do not expect a heavily interpreted show cave. The appeal is more local and rough-edged: a named landmark in a landscape where travellers are more likely to remember the road, the slopes, and the villages than any single attraction.