The clock tower also follows this rule of threes. In elevation it has a heavy robust base that is taller than the rest of the building. This is topped with another section that is more ornate, yet lighter, detailed with two columns to make three bays, and finally the actual clock and roof. The clock tower is modeled after the Campanile of St. Mark's in Venice, which had collapsed and was being rebuilt shortly before the construction of the station began. It is an interesting effect of the tower getting lighter with higher elevation. The bottom tier is mostly stone with only a vertical line of very narrow fenestration. The second tier becomes much lighter with the intercolumnation and having the stone wall set a distance behind the columns to give it the depth needed to create a sense of openness. The third tier completes the lightness by becoming narrower and employing a steep and slender roofline.