This huge sculpture at the heart of the Milly Forest was created in 1969 by Jean Tinguely and Niki de Saint-Phalle: a 22.5m-high head made of over 300t of steel covered in thousands of mirrors and turning cogwheels banging together. It incorporates a pool reflecting the blue of the sky, in homage to Yves Klein. Inside its strange labyrinth are works by artists dear to Tinguely: César, Marcel Duchamp, Larry Rivers…