If I think how Manchester will be seen in 2028, I can think of many characteristics, e.g., people, football, history but visually Manchester's skyline is now striking and unique. By 2028, Viadux2 might be at its full height. It's due to complete in 2031 so that's my guess.
Kinder Scout is the highest mountain (636m above sea level) in the Peak District (actually an ancient sea-cliff, formed 320m years ago in the Carboniferous. In that period, oxygen levels were up to 35% of the atmosphere compared to 21% today. That should give environmentalists something to ponder as they think about gases in ppm). Hayfield, a nearby village, is 278m above sea-level, so I can say that the local height of Kinder is 358m. Viadux 2 will be 246m (Beetham Tower, 169 m). Imagine a skyscraper 2/3 of the elevation of the Peak district's highest peak. That will be Manchester in the near future. I expect some UK cities will follow. The motivation is probably money for property developers, and I don't like that they co-exist with poverty and drugs, however in their shadows, at night, sunrise and sunset, they look stunning.