After the bombings during the Second World War under Cologne Town Hall the praetorium ruins – a Roman Governor's Palace – were discovered. Archaeologists are working here so far. They have found that the building dates back to the I-IV century BC, when Cologne, as a province of the Roman Empire, was declared the capital of Lower Germany. Praetorium is the largest Roman building in the Rhineland. Dimly lit corridors attract tourists, who want to learn more about ancient history. In addition to the ancient walls and utensils an attention should be paid to the sewage system, which was built by Roman engineers. To access the museum an integrated ticket for the Roman-Germanic Museum should be used.