This cave used to be a burial place, just like stone graves in Toraja. Latea Cave is a limestone cave which is estimated to be around 30 million years old. You would need to squat down and crawl through. Remember to bring mosquito repellent.
The main attraction within Tentena, which has beautiful clear water, adjacent warungs (and some home-stays under construction) and a peaceful vibe. 2 parallel bridges exist to bring you back and forth. It's worth exploring the opposite side of the lake for guesthouses, homestays, and warungs (kiosk / eatery).
By all accounts the Saluopa Waterfall - while a little tough to reach, about 12 km out of town - is one of the best available, notable for the lack of other tourists and businesses. There are approximately 10 drops, each of which you can bathe in. A nice relief from the heat of Sulawesi, and worth if considering if you have time. Toilets and restaurants at site.