This aerial view shows Bank Peninsula, with the snow-covered Southern Alps in the background. Akaroa Harbour is at the centre left. Volcanic activity between 11 and 6 million years ago led to the formation of two overlapping volcanic cones. After this activity ceased, the volcanic complex became eroded to half its original height, and deep valleys formed. The present harbours at Akaroa and Lyttelton were formed when the valleys were flooded as the sea level rose to its present height about 6,000 years ago.