Standing on the site of the original Byzantine city, the district known as Sultanahmet is the heart of tourist Istanbul, with many of the most important attractions dotted around it.
Begin your day in the subterranean depths of the Basilica Cistern, a 1,500-year-old building supported by 336 columns. Don’t miss the twin blocks carved into snake-haired Medusas.
Right across from the cistern is the greatest single building in a city full of wonders, the Hagia Sophia or Aya Sofya (£8.70, closed Mondays). It was a church, then a mosque and is now a museum.
