Quick answer: First time in Istanbul? Base in Sultanahmet or Beyoğlu, get an Istanbulkart for transit, and cross to the Asian side once.
Istanbul straddles two continents and several empires. Here’s how to begin.
When to go
Spring (April–May) and autumn (September–October) are mild and pleasant.
Getting around
Trams, the metro and ferries are efficient — get an Istanbulkart. Ferries across the Bosphorus are a highlight in themselves.
Where to stay
Sultanahmet for the historic sights; Beyoğlu/Galata for nightlife and a modern feel; Kadıköy for a local Asian-side base.
Top things to do
Hagia Sophia, the Blue Mosque, Topkapı Palace, the Grand and Spice Bazaars, and a Bosphorus cruise.
One tip
Dress modestly for mosques (women carry a scarf), and venture to the Asian side for the best-value food.