Mount Rushmore is one of America's most iconic landmarks, but there are dark mysteries behind its presidential faces; experts use cutting-edge tech and the latest science to reveal what lies beneath the rock and the secret history of its creation. 　　拉什莫爾山雕刻著美國四名總統(tǒng)的花崗巖頭像，這是世界上知名度最高的地表景觀之一，本集要挖掘這座現(xiàn)代建筑奇跡隱藏的秘密，它的建造秘訣是什么？為什么要把美國最著名的地標(biāo)景觀選址在偏遠(yuǎn)的南達(dá)科他州？