Original sentence: After 1980, during a major recession, may highrise construction projects were immediately halted.As a major business centre with a population of just over a million people, this is not suprising.Calgary has almost 50 million square feet of office space in the city, with over 32 million square feet in the downtown core.Calgary's downtown can easily be recognized by its numerous skyscrapers.Calgary's skyline includes the Petro Canada West Tower, which is the tallest building in Canada, outside of Toronto.Calgary's skyline is very recognizable.In total, there are 8 office towers that are 40 floors or higher.It was not until the late 1980s and through to the early 1990s that major construction began again.Some of these structures, such as the Calgary Tower are unique enough to be symbols of Calgary.The first skyscraper building boom occured during the late 1950s and continued through to the 1970s.The tallest of these (the Petro-Canada Centre), is the tallest office tower in Canada outside of Toronto.These buildings are iconographic of the city's booms and busts, and it is easy to recognize the various phases of development that have shaped the image of downtown.This is due in large part to the presence of numerous skyscrapers in around downtown
Edited sentence: - Calgary has almost 50 million square feet of office space in the city, with over 32 million square feet in the downtown core.- Calgary's skyline includes the Petro Canada West Tower, which is the tallest building in Canada, outside of Toronto.Calgary has a high percentage of it's workforce working in the core of the city, and this helps account for the high number of office towers.Calgary's downtown can easily be recognized by its numerous skyscrapers (including the tallest office tower in Canada outside of Toronto).Calgary, as a city of around million people is marked with a powerful high-rise skyline, which  belies its size and states clearly this is a dynamic, progressive, optimistic and entrepreneurial city.The skyline currently contains 8 office towers that are 40 floors or higher