In the centre of the picture, between the Baths of Caracalla and the aqueducts Appia and Marcia, 
spread the Augustus' administrative region nr XII. This region was also called  
Piscina Publica, 
because in the past one could find there a public swimming pool where the Roman youth 
used to learn to swim. It was a vast reservoir at the foot of the Aventine, which 
was also used as a watering place for horses and washing water. The indication about 
the place went up to 215 B.C. The name stayed even if the swimming pool disappeared 
with the time going. According to plans it should have been on the spot of the 
House of Q. Aiacius Censorinus, which we shall see further down. 
From the top of the Minor Aventine, 
taking as a starting point the 
Porta Nævia, one had to take the  
Clivus Delphini 
that went down across the region to reach the Via Nova. The 
Vicus Fortunæ Mammosæ 
was as well making a link between the centre of the Clivus Delphini and the Via Nova 

.