Starting in the 1850s, the industrialised countries abandoned their trade barriers and made their national exhibitions «universal». The idea was to mount an exhibition in a capital city the savoir-faire of the world's rapidly expanding industries. London started with the Great Exhibition at Crystal Palace in 1851. This was followed shortly by Paris in 1855. Two further exhibitions were held in both capitals, London in 1862 and Paris again in 1867. P.H. April 2010