The Isthmus of Panama ★★ (Geography) Exp:220 Fame:108 An isthmus in Central America. At its narrowest point, there is only 64km between the Caribbean Sea and the Pacific Ocean. Although it is not an unreasonable distance to build a canal, it is mountainous country with high rainfall and covered in dense forest. On top of that, construction would not be easy in a land with illnesses that produce high fevers.