Nottingham, England has a population of approximately 275,000 people and is the fastest growing city in England, and the second fastest in the whole United Kingdom. Most will remember the legend of Robin Hood, a tale that first arose in the Middle Ages. Robin Hood lived in Sherwood Forest and the Sheriff of Nottingham was his arch rival. While there is debate that the tales are accurate, or true at all, they have had an iconological impact on Nottingham; with many businesses and tourist centers using Robin Hood's image to lure tourists to their establishments. A major 19th century industry was tatting, or lace making. Some still practice the craft, but it really has no economic significance on the city. Nottingham is also known for having caves that were used as residences for the poorest citizens in the prior to the 18th and 19th centuries, when they were basically abandoned. However, they were used during World War II as air raid shelters. Some of these caves are open as tourist attractions.