In the 14 years between November 1838 and April 1854, Nicaragua had 27 different presidents, or roughly two per year.
It also has the only freshwater sharks in the world in Lake Nicaragua, which was named the 'Freshwater Sea' when it was first discovered; they believed they were looking at a sea, then discovered that it was freshwater when tasting it. They then made the interesting conclusion that it was a freshwater sea as opposed to a normal lake.
It has a very odd direction system. It has no street names; in cities the location is given relative to landmarks in the city, e.g. three blocks north from the fountain. In the city of Leon they refer to 'upstairs/downstairs' as opposed to 'east/west' and have multiple names for the same street intersection.