Well, The answer would be the number 3 why? because in the beginning when Ferdinand de Lesseps, a french engineer who built the swiss canal decided to create one in the isthmus of Panama due to its ideal location and width to save a lot of time and money on travels, they brought over from France workers and machines, used to create the swiss canal previously, but due to the clay soil and the tropical conditions they quickly broke, forcing workers to do most of the work manually. Also, due to the heat and the still water, mosquitoes carrying different diseases like malaria and dengue, swarmed the area biting and infecting the workers, ultimately killing most. Making them give up the whole project.
