A Wharf is a man-made structure on a river or by the sea, which provides an area for ships to safely dock. Some are very intricate, with multiple types of berth over a large area, and navigable channels, and others (like this one, below, from Australia) are more straightforward. A Wharf can contain quays and piers and will normally have buildings within it to service the ships (often warehouses and offices). Because of their abundance of unusual buildings and ready-made water features, unused wharfs are often converted into expensive retail and housing areas (for instance Canary Wharf and Butler's Wharf in London).