One of the earliest uses of clocks was in monasteries, to summon the monks to prayer at the proper time. Originally this was done by a water clock giving an aural indication of the hour, at which a monk rang a bell to summon the other brethren. Later, mechanical clocks performed that function. As the name suggest, the clock is in the shape of a tower, and as the hour is due to strike doors open at the base of the tower to reveal the figure of a monk who pulls a cord and apparently causes the hour to sound from a bell at the top of the tower.