This picture offers an opportunity to discuss the Millennium Dome, Victorian history and, indeed, the future.
The Great Exhibition of 1851 came right in the middle of the 19th century. What was happening then? Railways were about 20- years-old, with 2,000 miles of track; Queen Victoria was 32, influenced by her older husband, Prince Albert, who suggested the exhibition; the British Empire covered much of the world; industrial and transport revolutions were under way. America came to the fore as the Californian gold rush (1849) produced a wave of immigration and the "Wild West".
Discuss similarities. (Huge size, exhibitions showing off best talents, high cost, arguments about whether it is worthwhile and what should go in it.) Should we have big exhibitions like this? Are they fun? Educational? Vainglorious? Good economic sense (bring in tourists, sell British goods)? The Americans exhibited false teeth, artificial legs and the Colt pistol at Crystal Palace. What would you put in the dome to show the way to the future? Has anyone been to a big exhibition at the Natural History Museum, Epcot or Disneyland Paris?
Crystal Palace had more than 90,000 square metres of floor space and 13 kilometres (eight miles) of display tables - how big is that? (90,000 m2 about a dozen football pitches; eight miles is from our school to . . .?) What shapes can you see in the picture? How long ago was the exhibition? Crystal Palace burned down in 1936, so how long did it stand?
Ted Wragg is professor of education at Exeter University