Istanbul straddles two continents with the Hagia Sophia's Byzantine dome and Blue Mosque facing each other in Sultanahmet, the Grand Bazaar's covered market, and the Bosphorus ferry crossing between Europe and Asia.
Tulip Festival across Emirgan Park and Sultanahmet, Hagia Sophia walking pleasant, and Bosphorus ferries running smoothly without summer's tourist density.
Istanbul hits 30°C with humidity from the Bosphorus, but the Princes' Islands ferry stays cool and Bosphorus terraces in Bebek and Arnavutköy run dinner past midnight.
Istanbul Biennial in odd years from mid-September, Bosphorus haze-free for ferry crossings, and Grand Bazaar pleasant without summer cruise crowds.
Mild winter around 9°C with rare snowfall on the Hagia Sophia dome creating the city's most photogenic moments, and the bazaar's covered halls year-round.