Geography of Sheffield (Totley Brook passes south of Totley and meets Old Hay Brook at Needham's Dyke). The Sheaf flows northwards to join the River Don near Blonk Street Bridge in the city centre. This lower section of the River Sheaf together with the River Don, between the present Blonk Street and Lady's Bridge, formed part of the perimeter of Sheffield Castle. Porter Brook's source is just inside the Peak District National Park, to the west of the city, at Clough Hollow, also near Ringinglow. From here it flows eastward to meet the Sheaf, at a point now located underneath Sheffield Midland Station.
Sheffield indoor climbing centres. Sheffield was the UK's first National City of Sport and is now home to the English Institute of Sport – Sheffield, where British athletes trained for the 2012 Olympics. Sheffield also has close ties with snooker, with the city's Crucible Theatre being the venue for the World Snooker Championships. The English Institute of Sport hosts most of the top fencing competitions each year, including the National Championships for Seniors, Juniors (U20's) and Cadets (U17's) as well as the 2011 Senior European Fencing Championships. The English squash open is also held in the city every year. The International