- They're the largest and most demanding wildernesses of all.
是最大、最荒凉的无人区 - Nowhere else on Earth is seasonal change so extreme.
两极地区的季节变化非常极端 - It causes the ice to advance and retreat every year.
使得冰盖面积每年都在扩大和缩小 - And all life here is governed by that.
这里的一切生命都受其影响 - When the first polar explorers headed south,
第一批极地探险家前往南方时候 - giant cathedrals of ice marked their entry into uncharted territory.
经过这里的冰山就标志他们进入了未知领域 - Passing the towering spires,
在经过高耸的冰山的时候