Ball's Pyramid is an erosional remnant of a shield volcano and caldera that formed about 6.4 million years ago. It lies 20 kilometres (12 mi) southeast of Lord Howe Island in the Pacific Ocean. It is 562 metres (1,844 ft) high, while measuring only 1,100 metres (3,600 ft) in length and 300 metres (980 ft) across, making it the tallest volcanic stack in the world.