One hundred fifty one years old almost to the day as this image was made, the Clock Tower houses one of the most accurate mechanical clocks in the world. The clock and dials were designed by Augustus Pugin. The clock dials are set in an iron frame 23 feet in diameter, supporting 312 pieces of opal glass, similar to a stained-glass window. Some of the glass pieces may be removed for inspection of the hands. The surround of the dials is gilded. At the base of each clock dial in gilt letters is the Latin inscription: “DOMINE SALVAM FAC REGINAM NOSTRAM VICTORIAM PRIMAM” which means, "O Lord, keep safe our Queen Victoria the First."