A double-decker tram is a tram that has two levels. Double-deck trams were once popular in some European cities, like Berlin and London, throughout the British Empire countries in the early half of the 20th century including Auckland, Christchurch and Wellington in New Zealand; Hobart, Tasmania in Australia and in parts of Asia. They are still in service in Hong Kong, Alexandria, Dubai and Blackpool. Some double-decker trams had open tops. Blackpool tramway and Hong Kong Tramways are the only tram company in the world that operates double-deck trams now. Though a historical tramway in Auckland, New Zealand operates a restored double decker tram that operated in 1906 and has another in storage.