The Balobok Rock Shelter in Tawi-Tawi is evidence of human presence in Mindanao. Accidentally discovered in 1963 by Mt. Assiong Bangali of Tubig Basag Primary School as he took refuge during a sudden downpour. In 1966, Mr. Eric Casino reported it to the National Museum of the Philippines. Shell and stone adzes, flaked tools, and earthen wares were discovered here. READ: Featuring Tawi-Tawi - Solo-Backpacking in Mindanao