Until an embarrassingly big age, I thought the parthenon marbles were literal marbles (as in spherical glass). this was despite having seen them irl at the british museum, having to sketch them for art class etc. and STILL not making the connection between the ancient greek statues and the ‘marbles’. One day I guess I just thought, ‘well I better look up these damn marbles for myself and see what all the fuss is about’… and the penny finally dropped 💀