Ball's Pyramid is an uninhabited islet in the Pacific Ocean located 20 kilometres southeast of Lord Howe Island, between Australia and New Zealand. The steep rocky basalt outcrop is the eroded plug of a shield volcano and caldera that formed 6.4 million years ago. It is 572 metres (1,877 ft) high, 1,100 metres (3,609 ft) long and only 300 metres (984 ft) across, making it the tallest volcanic stack in the world.