When you climb the Bayon, the last complex temple if the Khmers, you are being watched.  The faces stare from fifty-nine towers, in the vast majority with four faces looking in four directions. You can't escape even when you go farther afield.  You pass beneath them when you exit through the gates of Angkor Thom.   They guard the entrances to minor temple like Ta Som.  They rise out of the jungle when you trek to distant outliers like Bantey Chmar.

Here is tiny sample from my 2015 visit.