Nişantaşı is upmarket Istanbul's residential heart — Cihangir's bourgeois counterweight, late-19th-c apartment buildings for the Ottoman professional class, boutique streets where the same class still shops a hundred and thirty years later. The walk runs from Osmanbey north through the boutiques and the old apartments to Atatürk's plain Şişli flat, where Mustafa Kemal planned what became the Turkish Republic.
Three kilometres, gently uphill north. Osmanbey metro is the entry. Abdi İpekçi Caddesi runs east — three blocks of Turkish fashion houses and international labels in the apartment shells. Cut north on Teşvikiye Caddesi past Abdülmecid's 1854 mosque, and into the Belle Époque streets where the Nişantaşı bourgeoisie still lives.
The walk's real centre is fifteen minutes further up: the Atatürk Müzesi in Şişli proper. The apartment Mustafa Kemal lived in 1918–19 before leaving for Samsun in May 1919 to begin the war of independence. Small, modest, frozen close to as he left it. Şişli-Mecidiyeköy metro is two blocks further if you want the M2 back to anywhere.