It’s really quite amazing how much they’ve been able to clean up St. Paul’s Cathedral in London. The first picture is from 1959, and the second is now. The blackness on the outside of it in the earlier photo was mostly caused by the nearby Bankside Power Station’s plumes of sulphuric dioxide gas and smoke, as well as the high usage of coal in London dating back to the Industrial Revolution. It has now been restored to its original glory, thanks to a decrease in industry and power generation in central London and the city increasingly moving to cleaner energy. Hurray for clean(er) air!