Ottawa is on the south bank of the Ottawa River and contains the mouths of the Rideau River and Rideau Canal. The older part of the city (including what remains of Bytown) is known as ''Lower Town'', and occupies an area between the canal and the rivers. Across the canal to the west lies ''Centretown'' and ''Downtown Ottawa'', which is the city's financial and commercial hub and home to the Parliament of Canada and numerous federal government department headquarters, notably the Privy Council Office. On 29 June 2007, the Rideau Canal, which stretches  to Kingston, Fort Henry and four Martello towers in the Kingston area, was recognized as a UNESCO World Heritage Site.