Sunsets over Bali are not to be missed. Any west-facing spot will do the trick but amongst the best are Jungut Batu beach on Nusa Lembongan, the ridge of high ground which runs the length of Nusa Ceningan and the highest point of Nusa Penida, Puncak Mundi. On a good day, the reflection on the ocean combines with the sun dropping magically behind Bali to create a truly breathtaking scene.
Nusa Lembongan hosts several really attractive and unspoit hidden white sand beaches and coves. Dream Beach and Sunset Beach in the south west are especially recommended. You can easily spend a whole day at either as they both have small beach-side restaurants. Neither beach is suitable for swimming though. The headland of Devil's Tear separates these two beaches and is a great spot to see the crashing waves of the Indian Ocean.
The whole southern coast of Nusa Penida has spectacular, high white limestone cliffs which will simply take your breath away. Even by the standards of Nusa Penida, the southern quarter is remote and inaccessible. The roads are difficult and in places distinctly hairy. But once you get there it will all seem worthwhile. Try anywhere along the south coast between Pendem and Batumadeg. Goa Karang Sari is a large limestone cave on the east coast of Nusa Penida about 4 kilometres north of Suana village. Find a local to help guide you and bring a flashlight. There are some impressive stalactites and other typical limestone formations. The entrance is a stiff climb from the road level. Of great religious and cultural significance.
Seaweed farming is a well-established micro industry here and areas around all three islands are planted and harvested. The seaweed is mostly destined for the north Asian cosmetics market. The best place to see this in action is the estuarine channel between Nusa Lembongan and Nusa Ceningan.