Glasgow is a port city on the River Clyde in Scotland's western Lowlands. It's famed for its Victorian and art nouveau architecture, a rich legacy of the city's 18th-10th-century prosperity due to trade and shipbuilding. Today it's a national cultural hub, home to institutions including the Scottish Opera, Scottish Ballet and National Theatre of Scotland, acclaimed museums and a thriving music scene. Greater Glasgow had a population of 1,199,619 at the 2001 census. Glasgow grew from a small rural settlement on the River Clyde to become the largest seaport in Britain. Glasgow is also well known in the sporting world for the football rivalry of the Old Firm between Celtic and Rangers. Winters are cool and overcast, with a January mean of 5.0 °C (41.0 °F), during the summer months (June to August) the weather can vary considerably from day to day ranging from relatively cool and wet to quite warm with the odd sunny day. The city has many amenities for a wide range of cultural activities, from curling to opera and ballet and from football to art appreciation; it also has a large selection of museums.