The iconic Büyük Mecidiye Mosque, also known as Ortaköy Mosque, offers free admission and is a must-see in Istanbul, typically requiring 30 minutes to an hour for a visit. Easily accessible via public transport to the bustling Ortaköy district, it's suitable for both solo exploration and guided tours, though solo visits offer more flexibility to explore the surrounding area. Open year-round, visitors should be mindful of prayer times when entry might be restricted, particularly on Fridays, and adhere to a modest dress code, including a head covering for women (often provided). Its stunning Neo-Baroque architecture against the backdrop of the Bosphorus Bridge makes it a prime photography spot, especially during early mornings or late afternoons for optimal lighting, and its vibrant neighborhood offers local food and crafts.