Greece has a long history dating back to ancient Greek city-states like Athens that developed one of the first known democracies. The Byzantine Empire carried on Roman traditions for 1000 years after the Western Roman Empire fell. Today, Greece has a president and prime minister, with over 98% of Greeks practicing Greek Orthodox Christianity. Agriculture remains an important industry, with farmers growing crops like cotton, wheat and olives, and Athens is the capital and largest city despite air pollution issues.