The former Italian monastery of Santa Fruttuoso in Northern Italy, now a museum, is accessible by boat, or by a serpentine footpath from Portofino through the mountains that affords tremendous views of the green slopes and glittering Mediterranean.
Of the narrow trail Nietzsche wrote: “I walked round the whole bay from Santa Margherita to beyond Porto Fino. This spot was all the more interesting to me, inasmuch as it was so dearly loved by the Emperor Frederick III. In the autumn of 1886 I chanced to be there again when he was revisiting this small, forgotten world of happiness for the last time. It was on these two roads that all ‘Zarathustra’ came to me, above all Zarathustra himself as a type;--I ought rather to say that it was on these walks that these ideas waylaid me."
Much more here.