Hermae (sing. herma) were installed in ancient Athens and other Greek cities. These peculiar phallus-endowed busts were used as land markers and protection against bad luck. Common in Athens apparently, perhaps less in other cities. Mostly representing the god Hermes, herald of the gods, god of lotteries and travel (pretty much anything with an unpredictable end). Other gods and heroes also showcased. Old or cheap ones in wood, but most in stone.
Also used in Rome at some point (Rome’s Hermes is Mercury), without the phallus.