Aerosmith — the quintet that has given the world 50 years of classic rock and some of the most enduring songs of all time, including ‘Dream On’, ‘Walk This Way’ and ‘Sweet Emotion’ — began its farewell ‘Peace Out’ tour last week in Philadelphia, US, with a two-hour set spanning its voluminous catalogue. This gives the world one last chance to see what earned these skinny guys from New England an exalted place in the pantheon of rock’s all-time greats.