I have covered the increasing blend of sports and politics before. In general, Americans like to separate the two hot-button topics, and many are greatly annoyed about how athletes and networks' political views are coming to the forefront when many believe they should "stick to sports."

This attitude does not exist in many other countries, where sports contest has small, but often existent effects on socioeconomic and geopolitical issues. When a polarizing issue exists, supporters on one side literally pick a side to support on the field (usually soccer, or football in this case because we're talking about global sports), with supporters of the political issues other side picking a rival team to root for. If you think the passion between Philidelphia Eagles and New York Giants fans is strong, then see what rivalries are on this list.

1. Eternal Derby, Serbia (Red Star Belgrade vs Partizan)

After the second World War, many countries in eastern Europe united to better compete with the democracies in the West. This included countries like the Soviet Union, and in this case, Yugoslavia. After the cold war, these communist countries all fell and split up into ethnic-based nation-states. For example, Serbia became independent after the fall of Yugoslavia, and Belgrade became the capital city.

Red Star and Partizan are the two biggest soccer teams in Belgrade and all of Serbia, and they are bitter rivals. Red Star fans are strong Serbian nationals. On the other hand, Partizan tried to keep Yugoslavia united for as long as possible.

This is a bitter issue for many Eastern Europeans, as the breakup of Yugoslavia resulted in civil war and ethnic cleansing in hope of one country "ruling" all their former domestic neighbors.

2. Derby Della Capitale (Lazio vs Roma)

The two teams share the city of Rome, the State of Lazio, and even the Stadio Olimpico, home to both sides.

Social classes have much to do with this one. Roma supporters accuse Lazio's supporters of being outsiders; not from the city of Rome. Lazio does have a fanbase that is historically working-class, while Roma's fanbase is more elite. While many blue-collar workers may root for Roma and many wealthy Romans may root for Lazio, the stereotype still holds largely true to this day.

Roma's fans will plaster stickers all over town that say Lazio Merda, which literally translates to "Lazio is shit."

3. Old Firm (Glasglow Rangers vs Glasgow Celtic)

4. El Classico (Barcelona vs Real Madrid)

This is probably the most well-known game on this list, and the politics behind this rivalry go far back. For centuries, Barcelona was the capital of Aragon, an empire that reached far into southern Europe. But when Spain took over this area, now known as Catalonia, in 1714, it was the last we would see of Catalan sovereignty-- for now.

Spain has continued to, in some people's eyes, beat their chest against the Catalans. Fransisco Franco was a dictator who ruled Spain in the mid 20th century who banned everything Catalan. While the current Spanish government does not ban the Catalan flag or language, critics say taxpayer money from Barcelona never returns, instead funding the deep pockets of Madrid.

So many Catalans take their pride-- and hopes for independence-- to FC Barcelona. Their arch rival is Real Madrid, the team representing Spanish nationalism free of division.

The two sides have blossomed into Europe's biggest soccer powers. The Spanish and European leagues are absolutely dominated by these two teams. The rivals have won six of Spain's last seven league titles and five of the last seven European titles. Meanwhile, the fight for Catalan independence has only gotten stronger, now a mega-polarizing issue in Spain.

The combination of politics and pitch action make this arguably the greatest rivalryin the world.