Curitiba is the capital of Paraná, Brazil. If you're heading for Iguaçu Falls from Rio de Janeiro or São Paulo, it's worth stopping by for a day or two.
Curitiba is one of the largest cities in the prosperous Southern region, and its population is largely descended from German, Ukrainian, Russian, Italian and Polish immigrants. The city is known to urban planners worldwide for its innovative public transit system. There is a great cidade velha (old city) in the center which was restored very well for its 319 years, but unfortunately much of it is covered in graffiti and only a few of the buildings are aesthetically pleasing as a result. There is a huge arts and crafts fair every Sunday in the old city that is well worth visiting.