Sharp Island has long been a favourite countryside destination and in recent years its unique geological features have gained attention. Its narrow shape is the result of a 140 million-year-long migmatisation of volcanic ash, lapilli, and lava. On the island, a mysterious pathway - a natural tombolo - appears at low tide and disappears when the tide bulges. How to get here: Take kaito ferry service at Sai Kung Pier to Sharp Island. The boat ticket only costs HKD30.