3. Mt. Roraima (Brazil) The mountain lies on the border of three countries viz. Brazil, Guyana and Venezuela. One thing that makes this mountain strange is its shape. What makes it weirder are the clouds and the fauna around the mountain peak. The peak of the mountain is considered as one of the oldest geological formations in the world. The plateau is believed to be formed by water and winds. But there is no explanation for why some of these species cannot be found anywhere else in the world.