Pera is what the European powers called this hilltop in the 19th century — the diplomatic quarter where French, British, German, Russian and Dutch consulates lived in stone buildings designed by people who'd worked on Paris boulevards. Pera Palace Hotel opened in 1892 to give Orient Express passengers somewhere to sleep, and from that point until the First World War this was where European Constantinople lived.
Three kilometres, gently downhill the whole way. Start at Taksim metro and walk south down Meşrutiyet Caddesi. Tepebaşı's 19th-century apartment buildings and consulate compounds line both sides; some are still working diplomatic missions. Pera Palace is the centrepiece — the marble lobby is free to walk through, the lift is the second-oldest in the city, and Atatürk's suite (101) has been a small museum since 1981. Agatha Christie wrote Murder on the Orient Express in room 411.
South past the British Consulate to the Crimean Memorial Church — G.E. Street, 1868, the architect of the Royal Courts of Justice in London. Polychrome English brickwork in an Istanbul side street.
End at Tünel. The 1875 funicular drops you to Karaköy in a minute, or walk back up İstiklal toward Taksim if you want a different kind of evening.