Lancaster's impressive Norman castle has dominated the city for nearly 1,000 years, still functioning as a crown court and former prison offering fascinating tours. The city prospered through maritime trade, reflected in fine Georgian buildings and the elegant Custom House designed by Robert Gillow. The Priory Church of St Mary is one of England's finest parish churches, while the Ashton Memorial in Williamson Park provides panoramic views across Morecambe Bay to the Lake District. The Lancaster Canal offers pleasant towpath walks through the city and surrounding countryside.