They usually contain a wide variety of types of drinks, and sometimes offer light snacks. Smaller versions of such bars can be found in a variety of places such as restaurants, private homes, corporate offices, cruise liners etc.
It is thought that the method of serving from a bar was invented by Isambard Kingdom Brunel, the great Victorian engineer, as a means of more quickly serving the sudden rush of customers caused by passenger trains arriving at the terminus of the Great Western Railway. Before then, the only method known was to wait at tables. If this is true, then the first bar would have been installed at the Great Western Hotel on Paddington Station, London.