Great Yarmouth is a coastal town in Norfolk, England. It is located at the mouth of the River Yare, 20 miles (30 km) east of Norwich. The town has been a seaside resort since 1760, and is the gateway from the Norfolk Broads to the North Sea. For hundreds of years it was a major fishing port, depending mainly on the herring fishery, but its fishing industry suffered a steep decline in the second half of the 20th century, and has now all but disappeared. The discovery of oil in the North Sea in the 1960s led to a flourishing oil rig supply industry, and today it services offshore natural gas rigs. More recently, the development of renewable energy sources, especially offshore wind power, has created further opportunities for support services. A wind farm of 30 generators is within sight of the town on the Scroby Sands.