Guanacaste is the 7th province of Costa Rica and the newest in the sense of becoming part of Costa Rica. The territory used to belong to Nicaragua, but due to many constant civil wars and violence, three of the major cities within Guanacaste got together to vote on whether to annex themselves to Costa Rica. These cities were Nicoya, Santa Cruz and Libera (capital city of Guanacaste). Out of all 3 cities only Liberia voted no, but due to the majority vote, the law was passed on July 25th of 1824 annexing Guanacaste to Costa Rica.
Now every 25 of July this is celebrated throughout the entire country. Everyone gathers for celebrations with dances wearing traditional attire, preparing food and reciting what are known as, "Bombas". Translation for, "Bomba" is "Bomb", yet it has nothing to do with war or anything like that. It derives from Bombetas or fireworks that are displayed in festivals with the difference that they are "verbal fireworks". So usually they express anything related to daily life. They may be romantic, funny, vulgar, etc. They usually tend to rhyme.
All types of traditional food is also served, there are rodeos, dances and much more.