The daily life of Athens centred in the Agora. If the streets approaching it were mean and dirty, the Agora itself, the centre of public life, was wide and spacious and surrounded by dignified and beautiful buildings. In shape it was a great open square, two sides of which were taken up with public buildings and temples. On the remaining sides were the Stoas or Porches. These consisted of a roof supported by a row of columns in front and a wall at the back. Each stoa was a covered walk, protected from the glare of the sun, the biting of the cold wind, and from the rain, and whatever the weather might be, the Athenian could always find a pleasant sheltered place where he could walk and talk with his friends. One of these Porches was known as the King's Porch. It was used as one of the law-courts, and on the wall at the back were inscribed the laws of Solon, and it was here that every archon had to take his oath of office. The most frequented of the stoas was the _Painted Porch_, so called because its wall was decorated with frescoes, one of which was a great painting of the battle of Marathon. The centre of the Agora was a great open space, part of it free for the public to walk in, and part of it full of booths and stalls where was sold everything needed by the Athenians. {194} There were three classes of people in Athens: the citizens, who were all free-born Athenians; the foreign residents who were called metics; and the slaves. In outward appearance there was often very little difference between them, but only the citizens might vote, and they alone had any privileges. The metics were generally well-to-do; they were merchants and bankers and helped very largely to create the wealth which made Athens great. The morning life of Athens centred in the Agora, but when the afternoon came, this was gradually deserted, and the Athenians who had gathered there earlier in the day went along the roads that led out of the city to the different Gymnasia. These were originally places devoted to the games practised by all Athenians, but they gradually became used more as parks, where the young men played games and the older men watched and talked. The Academy was the greatest of the gymnasia, and philosophers used to frequent it, and with their pupils discuss all the many things in which the keen and adventurous minds of the Athenians were interested. Plato, one of the greatest of the philosophers, was a well-known figure at the Academy.