All Romans utilized pottery lamps as a source of light. Throughout the Roman Empire, artificial light was prevalent, and earthenware oil lamps provided an alternative to candle light. Candles made of beeswax or tallow were less expensive but did not last as long. The oldest known piece of street furniture in Rome is a lampstand dating back to 75 B.C. Beeswax was harvested from hives located within the city walls of Rome. When enough candles had been collected, they were combined with olive oil to make one large batch of oil that was used throughout the year. This way the supply of wax would never run out even during times of scarcity. The making of candles was an important occupation for many people throughout the world. In Europe, Germany was the leading producer while France consumed more than it produced. The Greeks are credited with first introducing the idea of using lamps for lighting purposes. They used them to light their streets and houses. However, it was the Romans who developed this technology and put it to use on a large scale. By 225 A.D., there were approximately 3,000 lamps in use in Rome. They were placed about every 20 feet along the roads leading into the city from the surrounding areas. These roads were called luci di navio ("lights by the sea"), because they were usually well-lit at night.