Of the great commercial ports, Liverpool is by far the most pre-eminent. It was one of the greatest ports of Europe and one that carried most of the trans-Atlantic trade during the nineteenth century. It was the port of registry of the ill-fated White Star Line's Titanic which struck an iceberg and sank in 1912. Earlier associated with the slave trade, it was later the great emigration port for much of Northern Europe. The waterfront and commercial centre still epitomise Liverpool's importance and prosperity as a great imperial port, while the Albert Dock is the showpiece of a remarkable collection of docks along the Mersey estuary. The first wet dock was completed in 1715 and by the end of the eighteenth century further wet docks and graving docks had been added to the system.
The expression of commerical activity culminated in the magnificent trio of buildings on Pier Head - the Offices of the Mersey Docks and Harbour Board (1907), the Royal Liver Building (1910) and the Cunard Offices (1916). The proposed World Heritage Site focuses on the earlier surviving docks with the magnificent Albert Dock and Pier Head at their centre, and the immediate commercial hinterland comprising the western part of the Castle Street Conservation Area and the area to the east and south east.