4. Co-Operative Insurance Tower - Manchester (387 Feet)
One of the oldest skyscrapers outside of London, the CIS Tower was completed in 1962 and is a Grade II listed building. It is the second tallest building in Manchester and is the tallest office building in the UK outside of London. The age of the tower meant that it had to undergo major renovations after forty years, and the entire facade was covered in photovoltaic panels to help with green energy use.
