dash one's hope：打破某人的希望
be spared：免遭厄运；免受苦难；幸免
这个句子是结构比较复杂的句子,定语从句中套了定语从句：
dash the hopes of those ...打破那些人的希望；后面的who引导的是定语从句,修饰those,定语从句从who开始一直到句子结束；
in one of the few places on Earth some believe ...在这部分中,some believe开始一直到最后又是一个定语从句,some believe是插入语,这个定语从句修饰the few places,在定语从句中相当于the few places will be spared when ...；当然,这儿最好在some believe前加上that/which.
再如：He has tole some information that I think is very important.
Mrs.Smith didn't mentioned the questions I believe she would raise at the meeting.
整句话的意思：法国彻底打破了那些打算在世界末日12月21日来临前来法国避难的人的希望.人们相信地球上有几个末日避难地,而其中一个就在法国.