The Thames Frost Fairs in London
www.historic-uk.com
Between 1607 and 1814, there were a total of seven major frost fairs held on the frozen River Thames in the heart of London. These fairs hosted bull-baiting, pop-up pubs, and even saw a king or two taking part in the festivities!

(Added as a matter of curiousity, not to divert or disavow the our very real AGW.) This occurence is usually blamed on the ‘Little Ice Age’ … cause still uncertain. The LIA is implicated in 500 years of misery for many Europeans. https://en.wikipedia.org/wiki/Little_Ice_Age