Crystal Palace I can't remember the exact date somewhere in the Mid 19th century, the government couldn't predict how the building would cope with a large crowd so they had 300 workmen walking round and round in circles simultaneously then at a pre-arranged signal they would all jump, thus testing how robust the structure wasbefore they went ahead with the grand opening by Queen Victoria. Not sure if this is what you're looking for as it's not a gallery but I remember it from studying Queen Victorias reign in History