北极，为什么没有陆地？

The North Pole sits on top of the world. 北极在地球的最顶端。 But there is no land under the ice. 可冰层底下并没有陆地。 The ice just floats on the deep ocean. 冰盖只是浮在深海上面。 Polar bears walk across the floating ice. 北极熊在浮冰上走来走去。 Antarctica below has a whole big land. 南极底下却是一整块大陆。 That is the big difference between them. 这就是南北极最大的不同。