The Pnyx (/nɪks, pəˈnɪks/; Ancient Greek: Πνύξ; Modern Greek: Πνύκα, Pnyka) is a hill in central Athens, the capital of Greece. Beginning as early as 507 BC, the Athenians gathered on the Pnyx to host their popular assemblies, thus making the hill one of the earliest and most important sites in the creation of democracy. The Pnyx is located less than 1 kilometre (0.62 mi) west of the Acropolis and 1.6 km south-west of the centre of Athens, Syntagma Square.
The Pnyx is a small, rocky hill surrounded by parkland, with a large flat platform of eroded stone set into its side, and by steps carved on its slope. It was the meeting place of one of the world's earliest known democratic legislatures, the Athenian ekklesia (assembly), and the flat stone platform was the bema, the "stepping stone" or speakers' platform. As such, the Pnyx is the material embodiment of the principle of isēgoría (Greek: ἰσηγορία), "equal speech", i.e. the equal right of every citizen to debate matters of policy.
The other two principles of democracy were isonomía (Greek: ἰσονομία), equality under the law, and isopoliteía (Greek: ἰσοπολιτεία), equality of vote and equal opportunity to assume political office. The right of isēgoría was expressed by the presiding officer of the Pnyx assembly, who formally opened each debate with the open invitation "Tís agoreúein boúletai" (Greek: "Τίς ἀγορεύειν βούλεται;", "Who wishes to speak").
The Pnyx was used for popular assemblies in Athens as early as 507 BC, when the reforms of Cleisthenes transferred political power to the citizenry. It was then outside the city proper, but close enough to be convenient. It looks down on the ancient Agora, which was the commercial and social centre of the city.