The Great Pyramid of Giza is a fine example of the use of the golden ratio, golden triangle and golden rectangle. The pyramid, one of the Seven Wonders of the World, is also one of the earliest examples of the ratio's use. When you halve the square base of the pyramid and draw a vertical line up to the pyramid's peak, the line, when connected to one of the angled sides of the structure, forms a "golden triangle" with the ratio 1.62, the golden ratio.
The Parthenon on the Acropolis in Athens is another fine example of the multiple use of the golden ratio. The floor plan of the Parthenon is a "golden rectangle" that exhibits a ratio of length to width in the proportion of 1.618. The same ratio can be found when comparing the height of the temple with that of the columns. The temple was designed by Iktinos in the fifth century B.C., and he used the golden ratio throughout its design.
Another good example of the use of the golden ratio in architecture and monuments can be seen in the CN Tower in Toronto, Canada. The total height of the tower, which is the tallest freestanding structure in the world, is 553.33 meters (1,815.39 feet), and the height of the observation deck with its rotating restaurant is 342 meters (1,122 feet), a ratio of 1.617, an aesthetically pleasing picture.
The golden ratio can be seen in the design of the Cathedral of Notre Dame in Paris. Masons started building Notre Dame in the year 1163, not completing the building until nearly 200 years later. The foundations were built upon those of a Roman temple to Jupiter, and show several examples of the golden ratio, most easily seen in the western façade of the cathedral, both in the overall structure and in numerous substructures.
