Zeno the Stoic, Corfu, Greece

Zeno was the first existentialist. But unlike Sartre, the void didn't make him sick, it made him thoughtful. Essentially, if you accept the universe as it is, it leaves you free to think deep thoughts rather than worrying about what you can't change. He did a great deal of his teaching in the Athenian Agora, at one of the stoa, thus earning him the title Stoic.
This is at the Achilleion Palace in Corfu, a giant summer home (5 stories tall) of an Austrian princess who was obsessed with Achilles.