ity ▁in ▁ 1 8 6 9 . ▁On ▁the ▁piano ▁nob ile ▁is ▁an ▁assemb lage ▁of ▁port ra its ▁of ▁the ▁Grand ▁Masters ▁of ▁the ▁Order . ▁ ▁Site ▁The ▁site ▁is ▁reached ▁by ▁Via ▁Santa ▁Sab ina , ▁which ▁ends ▁in ▁the ▁small , ▁pictures que ▁Pia zza ▁dei ▁Caval lier i ▁di ▁Mal ta ▁en closed ▁on ▁two ▁sides ▁by ▁the ▁cy press es ▁of ▁the ▁garden ▁of ▁the ▁Bened ict ines ▁backing ▁the ▁fant asy ▁screen ▁of ▁ob el is ks ▁and ▁ste le ▁constructed ▁in ▁ 1 7 6 5 ▁to ▁designs ▁by ▁Giovanni ▁Batt ista ▁Pir an esi , ▁one ▁of ▁the ▁very ▁few ▁executed ▁designs ▁by ▁this ▁et cher ▁of ▁Roman ▁views ▁who ▁pr ided ▁himself ▁on ▁being ▁an ▁architect . ▁A head ▁r ises ▁the ▁Ne o - R oman es que ▁camp an ile ▁of ▁the ▁Church ▁of ▁San ▁An sel mo ▁( 1 8 9 3 - 1 9 0 0 ) ▁attached ▁to ▁the ▁international ▁Bened ict ine ▁sem inary ▁( Sem in ario ▁Intern azionale ▁Bened ett ino ). ▁ ▁Key hole ▁▁ ▁At ▁the ▁northern ▁side ▁of ▁the ▁square ▁the ▁monument al ▁entrance ▁screen ▁is ▁located , ▁also ▁designed ▁by ▁Pir an esi ▁under ▁commission ▁from ▁Card inal ▁Carlo ▁Re zz on ico , ▁nep hew ▁of ▁Pope ▁Clement ▁XIII . ▁The ▁Villa ▁is ▁arg u ably ▁best ▁known ▁for ▁a ▁small ▁key hole ▁( Il ▁Bu co ▁D ella ▁Ser r atura ) ▁in ▁the ▁arch - head