The Nikumaroro Atoll in the South Pacific Ocean is the subject of today’s Image of the Day from the NASA Earth Observatory. The Nikumaroro Atoll can be found halfway between Hawaii and Australia about 1,000 miles from Fiji and is a sandbar built on a coral reef that sits on top of a volcano. It measures roughly 4.7 miles by 1.6 miles and is surrounded by very deep ocean water.