Croatia's Baseball League isn't messing around. They've played several times in the Baseball World Cup, and the city of Zagreb was a hosting venue for the Cup in 2009. By all accounts, U.S. military men introduced the game to Croatia. (Some say around 1918 during the first World War, while others claim it came during World War II.)
In 1975, a group of teachers decided to organize a real club. In 1978, the first game was played in the town of Split, between the Split players and a team from the nearby town of Ljubljana in Slovenia. Split won, 20-1. And Split embraced baseball; there's even a book, "Nima Baluna do Baseball Baluna" that details the history of the sport in the city. (The title translates to "There's No Ball Like Baseball.") Now, the Croatian league has a regular season, and the National Team is ranked an impressive 25th in international rankings.
All the big cities have teams that play against one another; there are 13 teams altogether. There are also youth and cadet leagues (boys and girls ages 8 to 16), while only boys 16 and over can play in Junior and Senior leagues. Unfortunately, there are only two baseball stadiums in Croatia (in Zagreb and Karlovac), according to the Croatian Baseball Association's Web site. In other cities, a stadium is outfitted with bases and a pitcher's mound to give the players a makeshift field.