Which of the following do the Crystal Palace by Paxton and Eiffel Tower by Eiffel have in common?
A) They both held exhibitions and both used elevators
B) They are both made of steel and both are still standing today
C) They were both made of iron and were associated with Universal Expositions (World's Fairs)
D) They both broke records: the Crystal Palace for the tallest monument and the Eiffel Tower for the largest enclosed space