In 1940 Donald Bailey of Britain's Royal Engineers used his Erector Set to design the portable Bailey Bridge, which spanned creeks and rivers and was hailed by Eisenhower as one of the three most important technological advancements of the war, along with radar and heavy bombers.
There is a wooden display case, about the size of a folding bridge table, showing off a portable retrospective he created for the Paris Exposition Universelle in 1889.