Part an agreement with Natural England was that the land where the existing 1970s visitor centre was located would be restored to wood pasture. Some portions of the forest retain many very old oaks, especially in the portion known as the Dukeries, south of the town of Worksop, which was so called because it used to contain five ducal residences. The River Idle, a tributary of the Trent, is formed in Sherwood Forest from the confluence of several minor streams. Sherwood attracts around 350,000 tourists annually, many from other countries. Each August the nature reserve hosts an annual, week-long Robin Hood Festival. This event recreates a medieval atmosphere and features the major characters from the Robin Hood legend. The week's entertainment includes jousters and strolling players, dressed in medieval attire, in addition to a medieval encampment complete with jesters, musicians, rat-catchers, alchemists and fire eaters. Throughout the year, visitors are attracted to the Sherwood Forest Art and Craft Centre, which is situated in the former Coach House and Stables of Edwinstowe Hall in the heart of the Forest. The centre contains art studios and a cafe, and hosts special events, including craft demonstrations and exhibitions. Sherwood Forest is home to the famous Major Oak, which, according to local folklore, was Robin Hood's principal hideout. The oak tree is between 800 and 1,000 years old and, since the Victorian era, its massive limbs have been partially supported by an elaborate system of scaffolding. In February 1998, a local company took cuttings from the Major Oak and began cultivating clones of the famous tree with the intention of sending saplings to be planted in major cities around the world. The Major Oak was featured on the 2005 BBC TV programme "Seven Natural Wonders" as one of the natural wonders of the Midlands. Thynghowe, an important Danelaw meeting place where people came to resolve disputes and settle issues, was lost to history until its rediscovery in 2005–06 by local history enthusiasts amidst the old oaks of an area known as the Birklands. Experts believe it may also yield clues as to the boundary of the ancient Anglo Saxon kingdoms of Mercia and Northumbria. English Heritage had inspected the site, and have confirmed it was known as "Thynghowe" in 1334 and 1609.