This is an underground site discovered by chance in 1923, the hypogeum in via Livenza, in Rome
It is located 9 metres below the street level. At present only the north wall, decorated with fresacoes and mosaica and the adjoinining deep basin can be seen. Experts are still debating what the hypogeum was originally meant for (maybe a nymphaeum or a fountain protecting an ancient natural water source?). In any case, it dates back to the middle of 4th century A.D.