Porta Alchemica
Queen Christina had an alchemical laboratory in Riario palace attended by people like the esotericists Giuseppe Francesco Borri, and the learned Athanasius Kircher possessor of the mysterious Voynich manuscript of enigmatic scripture full of magic symbols. According to a legend the same Porta Alchemica was built in 1680 as a celebration of a successful alchemical transmutation occurred in Riario laboratory.