Beginning of Essay
Picture in your mind the skyline of downtown Toronto. There's the CN Tower, of course, and the 72-floor First Canadian Place, the city's tallest skyscraper. Cascading from there are the assorted banks and hotels and insurance towers. Now, use your imagination ....

Middle of Essay
.... face? What materials would you use? And where would you put it? Building a superskyscraper, the first thing you would need is a considerable slice of real estate. Tall buildings require a large base to support their load and keep them stable. In general, the height of a building should be six times its base, so, for a skyscraper 900-m tall, you'd need a base of 150 square m. That much space is hard to come by in, say, downtown Toronto, forcing you to look for an undeveloped area, perhaps the Don Valley ravine, next to the Science Centre. Bear in mind though that the Don Valley is overlain by loose sand and silt, and tall buildings must stan ....