Anyone recognize this picture?
It's the Great Exhibition of works and Industry for all Nations, sometimes referred to as the Crystal Palace Exhibition in reference to the temporary structure it was held in. It was an international exhibition and took place in Hyde Park, London, from 1st May to 15th October 1851 and was the first in a series of World Fairs that became popular in the 19th century.
It became a tremendous success story and is commonly referred to as the predecessor to modern day exhibitions as well World Expos that exist today.
If you would like to more here's the Wikipedia link...