Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. Gaywood River - Gaywood River (sometimes known as the River Gay or River Gaywood or in King's Lynn as the Fisher Fleet) is a tributary of the River Great Ouse in the west of the county of Norfolk. Its source is 11 metres above sea level northwest of the village of Gayton in Derby Fen Map Reference TF 705 209. It runs for 6.7 miles (10.8 km) to its outflow into the River Great Ouse in the town of King's Lynn. Derby Fen is the remnant of a valley fen system once found in these parts.
The answer to this question is:
Natural Place