at opposite directions

There are two archaeological sites in Sicily , into opposite directions,

among my favourite ones.

up above the fortress of Eurialo's Castle 

one of the jewels of the ancient Greek Syracuse

and down below 

some pictures taken around  the North gate of the ancient Selinunte 

and  in its defence system

They are indirectly correlated each other 

for being one of the outmost examples 

of an active defense system