It served as a meeting place for guests on hot summer days .
The fountain also has its own grotto , the Grotto of Venus , designed by Pirro Ligorio , and built in 1565 -- 68 .
Grotto of Venus served as a meeting place for guests on hot summer days .
The fountain also has its own grotto , the Grotto of Venus , designed by Pirro Ligorio , and built in 1565 -- 68 .