A suggested travel itinerary for Istanbul, Turkey might include:
Day 1:
Visit the Sultanahmet neighborhood, home to famous landmarks like Hagia Sophia, the Blue Mosque, and the Topkapi Palace.
Explore the Grand Bazaar, one of the largest covered markets in the world.
Take a stroll along the bustling streets of the Eminönü neighborhood and cross the Galata Bridge to explore the Karaköy neighborhood.
Day 2:
Visit the Chora Church, one of the best-preserved Byzantine churches in Istanbul.
Explore the trendy neighborhood of Beyoglu and its famous street, Istiklal Avenue.
Visit the Taksim Square, a central square in Istanbul that is the starting point of Istiklal Avenue.
Day 3:
Visit the Dolmabahce Palace, a 19th-century palace that was the residence of the Ottoman Sultans.
Visit the Bosphorus Strait and take a boat tour to admire the beautiful views of the city and its surroundings.
Visit the Princes' Islands, a group of islands in the Sea of Marmara that offer scenic views, relaxed atmosphere and a taste of Ottoman architecture.
This itinerary is just a suggestion and can be modified based on individual interests and time constraints.