Which city hosted the first World Expo, held in 1851?

London hosted the first World Expo, the Great Exhibition of 1851.

The Great Exhibition of the Works of Industry of All Nations opened in London’s Hyde Park on 1 May 1851. Its main building, the Crystal Palace, was a vast prefabricated structure designed by Joseph Paxton and became an engineering landmark because of its extensive use of iron and glass.

The exhibition displayed industrial products, scientific instruments, artworks and manufactured goods from Britain and other countries. It was promoted by Prince Albert and Henry Cole, who wanted an international showcase for industry, innovation and commerce. More than six million visits were recorded during its run from May to October.

The event established the model for later international expositions, now commonly called World Expos and regulated by the Bureau International des Expositions. The Crystal Palace was dismantled after the exhibition and reconstructed in south London, where it stood until a fire destroyed it in 1936. Later famous expos included Paris in 1889 and Chicago in 1893.