and the streets create small rooms mostly inaccessible for keen winds. These so-called rooms also stimulate the social life on the streets. Stortorget – the main town square in central Östersund is one of six "closed squares" built in Sweden, the others being the ones in Uppsala, Karlstad, Vimmerby, Piteå and Haparanda. It was created through indentation in four different blocks to deliberately create an open air room with openings to every direction, a style deriving from how cities were planned during the Renaissance. However the town square lost its original shape when it was opened up and expanded towards the lake. Stortorget has long been the city's main market place and core; it is also here that the thousand-year-old market Gregorie market is held each year in March. The city festival Storsjöyran has Stortorget as its main centre. Districts and housing estates Before Östersund was established the population in the area was very scarce. In Odensala and Torvalla older settlements existed; the name Odensala can be derived from the Viking age and the Halls of Odin (though Torvalla means 'dry wealds' with no reference to Thor). These two villages were later incorporated into Östersund and are today two major urban districts. Besides them the urban districts of Staden, Norr, Söder, Odenslund, Karlslund, Körfältet Odenskog, Lugnvik are found on the mainland of Östersund. On the island Frösön are the six urban districts Hornsberg, Östberget, Frösödal, Mjälle, Valla and Härke. The central parts of Östersund are a part of the urban district Staden – 'the city', which has become synonymous with Östersund for many people living in the nearby villages and towns. As Östersund is the only city in the area and nearest city for many it is common to call it , though the dative form has increasingly grown unusual. The residents of Östersund are referred to as , though local people in rural areas call them 'towners', and 'towner', in singular. Landmarks The most well-known landmark of Östersund is the national romantic Östersund City Hall (). It is 51 meters tall and contains 136 rooms. It is the greatest constructional symbol of the National Romantic architecture in Östersund. The city hall looks almost like a fortress and has a particular connection to the local art of Jämtland. The bell tower is of typical Jamtish design, shaped like an onion. Local sculptor Olof Ahlberg (1876–1956) made most of the sculptural