定语从句fromwhere课文上有一句Wewalkedfortwoandhalfandhourstogetthere--firstupamountaintoaridgefromwherewehadfantasticviewsandthendownasteeppathtothevalleybelow.为什么用fromwhere啊这里的先行词是

　　定语从句fromwhere

　　课文上有一句

　　Wewalkedfortwoandhalfandhourstogetthere--firstupamountaintoaridgefromwherewehadfantasticviewsandthendownasteeppathtothevalleybelow.

　　为什么用fromwhere啊这里的先行词是ridge吗那是不是用fromwhich也可以?

　　这句话中文意思是怎样?