You will not see elsewhere as many stray cats in one place as by walking the streets of Athens. There are thousands. They sit atop stone walls, stalk for food outside of restaurants, sleep on tree branches and dart into broken windows of crumbling buildings.
Most of the cats are friendly or indifferent. Sometimes, if you crouch down, they’ll come closer and rub up against your hand or legs or they’ll plop down at your feet, bellies up.
Animal protection in Greece depends mostly on charities and more of a more ad-hoc, on a neighborhood by neighborhood level. People who care about their neighborhood cats sometimes provide medication and sterilisation to them – at least to those cats who trust them enough.