Instructions
Go to Terme di Traiano in the Antico District in Rome, Italy. It is located East of the Colosseum in Rome. Enter the shrine. The entrance is located near the Southeast corner of the ruins of Terme di Traiano.
Look for a flight of stairs, at a low point of the terme and head down them. Press the four switches and then jump down into the hole to land in the hidden pool beneath it to enter the secret location of the Golden Palace of Nero located beneath the baths.
Reach the second secret location by traveling to the Piramide Cestia. The entrance is near the pyramid, and leads you down into the Catacombs of Rome, or the Catacombe di Roma.
Make your way over to the Colloseo or Colosseum in Rome. Find the lair entrance at ground level between the inner and outer wall so of the Colosseum, behind the Passion play stage.
Go to the Basilica di San Peitro. The entrance to the secret location is located outside of the Basilica, on the right side of the stairs that lead to the inner sanctum of the church.
Find the next secret lair by heading to the Palazzo Laterano. The entrance is in one of the gardens of the palace.
Reach the last secret location by going to Terme di Diocleziano. It can be found in the Cloaca Maxima in the aqueducts.