A. The Colosseum.

B. Part of the Cœlian Hill, on which the Claudium stood.

C. Part of the Palatine Hill.

a. Summa Sacra Via.

a*. Clivus Triumphalis.

b. Meta Sudans.

c. Arch of Constantine.

d d. Passage of Commodus.

e. Site on which the steam-engine was placed in 1874-5, to pump out the water coming from this point.

f. Piscina of the time of Nero.