Mfangano Island is home to two ancient rock art sites and it is possible to trek to see this Ancient Rock Art.
These rock art paintings are located in Mawanga Cave on Mfangano Island! There is another set of cave paintings at the top of the mountain on Mfangano Island at a site called Kwitone these ones are larger and more impressive. The interesting thing about the geometric paintings at Mawanga is that although they were originally painted by the Twa (Batwa) possibly more than a thousand years ago, they were actually used by the local Suba people for rain making ceremonies right up until the 1980s when the missionaries told them to stop. When the Suba arrived from Uganda as refugees around 200 years ago they found the Twa there who were hunter gatherers like the Bushmen. The Suba (Abasuba) gradually appear to have absorbed them along with some of their belief systems. Trust for African Rock Art (TARA) have recorded similar rock art (paintings and engavings) in northern Kenya, Uganda, Tanzania and Malawi and know that it exists in Zambia, Congo, Gabon and Senegal.
The Mawanga cave is especially interesting because it looks out towards Nsenze Island which is the sacred island of the Wasabi clan. They say that whenever there was a severe drought in the land there was always food to be had on this island, where a large python also lived, needless to say! It was almost as if the rain-making vibes were beamed out from the cave onto the island so that it would always provide food! TARA have recorded similar oral legends about the rain making power of the circles and spirals in eastern Uganda and they know one site there that was used for rain-making rituals until very recently and another one where people hold fertility rituals to this day. Interesting that in places like Utah in the USA similar spirals and circles are associated with fertility!
Information on the sites from Trust for African Rock Art (TARA).