Kāneʻohe Bay, at 45 km2 (17 sq mi), is the largest sheltered body of water in the main Hawaiian Islands. This reef-dominated embayment constitutes a significant scenic and recreational feature along the northeast coast of the Island of Oʻahu. The largest population center on Kāneʻohe Bay is the town of Kāneʻohe. In August 2010, Pirates of the Caribbean: On Stranger Tides was filmed on the bay. Geologically, Kāneʻohe Bay forms part of a former caldera of the Koʻolau volcano. In prehistory, most of the volcano catalysmically slid into the Pacific Ocean, leaving behind only the Range and the Bay.