1. v
This is the Pre World War I Map of the Balkans. As shown, there are very few countries, and those that exist are the stalwarts of the area, which are mostly present throughout

2. This is the post World War I map, and there have been many changes
This is the post World War I map, and there have been many changes. Bulgaria has grown, as has Romania, but Montenegro and Serbia merged into Yugoslavia, and the Ottoman Empire fell, leaving the Turkish country, Turkey.

3. This is the Post WW2 and Fall of the Wall map, combined
This is the Post WW2 and Fall of the Wall map, combined. You can see the 1991 borders in the dashes. As you can see, Yugoslavia broke up into six different countries, while most other borders haven’t really changed. For a while, it was Serbia and Montenegro in one county, until 2004

4. This map is modern, with the final borders being found, and being similar to the 1991ish map. The only major difference is Kosovo, which is a highly contested new country as of 2008, having separated from Serbia.

5. As seen above, the Balkan region is quite rocky, and not very conducive to travel or trade. Also, that probably contritbutes to the numerous different ethnicities and religions in the area.

6. The mountainous terrain and former communist nature of the area probably contributes to the lack of EU members in the Balkans.

7. This map shows that only two of the modern countries were not communist before the fall of the Berlin Wall in 1991.

8. As seen above, there are at least 12 different major ethnicities in the Balkans, and numerous ones in the Bosnia region, the reason for the Bosnian War.

9. The majority of the Balkans is Orthodox, though parts of Bosnia and the former northern part of Yugoslavia are very diverse, another reason for the Bosnian War in 1994.