When the first polar explorers headed south, 第一批极地探险家前往南方时候
Each year explorers chart over a hundred miles of new cave passages. 每年 探险家们都会测绘 上百英里新的洞穴通道
As the explorers went deeper into the cave, 随着探险家们深入洞穴
When the first explorers descended, 第一批探险家进入这个洞后
but cave explorers were soon to make an even more astonishing discovery. 但是洞穴探险家们 很快又有了更惊人的发现
Explorers entering this dangerous cave 探险家们进入这个危险的山洞时
Early explorers told tales of lakes that smoked, as if on fire. 早期探险家看到这种湖面上“冒烟”的情景 还以为是湖底着了火