Tarragona is a city located in Catalonia, Spain on the Mediterranean coast. It has a population of around 130,000 people and borders the provinces of Castellón, Teruel, Zaragoza, Lleida, and Barcelona. Tarragona has a well-preserved historic old town containing Roman ruins such as an amphitheater, circus, walls, and aqueduct. However, it also has a large industrial sector and nuclear power plant, making it one of the most polluted areas in Catalonia.