Clock tower
Clock towers are a type of building which have a big clock and have one or more clock faces on the upper walls. Many clock towers are built alone but they can also be with or be located on top of another building. Some other buildings also have clock faces on their outer walls but these buildings are used for other purposes.
Clock towers are common in many parts of the world with some being very well known. One example is the Elizabeth Tower in London (usually called "Big Ben", but this name only belongs to the bell inside the tower).