The Kalandula Falls are one of the largest waterfalls in Africa by volume and arguably Angola's most famous tourist attraction.
At the Kalandula Falls the 400-metre-wide (1,300 ft) Lucala River drops 105 metres (344 ft) with a breathtaking roar. The falls are best viewed during the rainy season that runs from February to April.
The road from Luanda is not in good condition. However, you should be able to make it there without a 4WD, emphasis on should.
You can procure a guide for around Kz5000 to take you to some of the better viewpoints.
There is a hotel at the falls, Pousada Calandula. The other alternative if you're staying the night is to find a hotel in Malanje. You probably don't want to be driving the road from the falls at night, so time your departure accordingly.