The Great Smog of London remembered 60 years on
5 December 2012 Last updated at 15:57 GMT
Sixty years ago thick smog descended on London, contributing to the deaths of an estimated 4,000 people.
The four-day "pea-souper", while worse than usual, was a familiar experience for Londoners.
Visibility was so poor buses and taxis ground to a halt, forcing commuters to hurry underground to use the Tube.
The legacy of the Great Smog was the Clean Air Act of 1956 which introduced a number of measures to reduce pollution.