Cartagena's walled city has one of the finest collections of colonial door knockers in the Americas — ornate cast-iron or brass fixtures that were not merely decorative but carried specific social meaning in the colonial hierarchy. Fish, lizards, lions, hands, and other forms each indicated the status, profession, and religion of the household.
Spotting and photographing the knockers is one of the more rewarding ways to walk the streets of the old city — it gives you a reason to stop and look closely at doors you'd otherwise walk past. The neighbourhood of San Diego (the residential district within the walls) has the highest concentration of old colonial houses and therefore the most variety. Several guided walking tours of the city make the door knockers a central theme.