London's Great Exhibition - Acton, 1870 ??

17 October 1849, Plans for a Great Exhibition of the Works of Industry of All Nations were announced at a banquet at Mansion House, London. In January 1850 a Royal Commission, headed by Prince Albert, was formed to organise the event. The Commission had just over a year to complete its task before the Exhibition was due to open on 1 May 1851.

https://fooddeserts.org/images/000London.htm

If the Great Exhibition, Crystal Palace, London, had been HS2....it would probably have been held in 1870, somewhere out in Acton.

They did things much quicker in 1850 than we do now.