The island is the highest point of an upward bulge in the ocean floor caused by the flexing of the earth's crust plate (the Indo-Australian plate) as it moves northwards pushing against another plate (the Eurasian plate). This means that the island is moving northwards at a rate of 6 cm per year so you'll have to hurry if you want to visit as the island will slip out of sight into the Java Trench in about 3 million years!

The island is about 135 square kilometers in size - smaller than many Australian outback farms! It rises 360 meters above the surface of the Indian Ocean.

Christmas Island is made up of mostly limestone rock - a product of the fringing coral reefs formed during the early formation of the island as it rose out of the sea. - which means that there are plenty of caves to explore - both above and below the water line. A recent speleology expedition discovered the second largest cavern in the southern hemisphere here. After ten hours of walking, climbing, squeezing through tunnels and squelching through puddles up to their armpits as they made their way in to Bishops Cave I suppose they must have been pretty excited. They called the cavern Phantasmagoria. It sounds a bit corny in the cool light of day!

One finds oneself on top of a former oceanic vulcanoe that was never connected to any landmass. Anything reaching the island has come by water or air and once there, bred into new and unique species which means that there are many forms of plants and animals found nowhere else on earth.
The major attraction is the National Park which covers about 63% of the island and includes the ocean for 50 meters out from the low tide mark.
In this park you will find most notably rare crabs, birds and plants above the water while below the water large pelagic fish swim over steep drop offs falling away from pristine coral reefs.