My family plans to visit Istanbul in mid-September, and we consider Hagia Sophia and Topkapi Palace as our must-visit sites. I have a few questions:
1. Hagia Sophia offers free admission, but there are various skip-the-line small group guided tour options available. Is it necessary to choose one of these options? Will there be long lines to enter? Can visitors explore the upper part of Hagia Sophia without a guide?
2. For Topkapi Palace, how can we purchase online tickets in advance? The website lists the prices but does not provide a function or button to purchase tickets. Also, is it advisable to have a guide with a skip-the-line option for this visit as well?
Thank you in advance for your assistance.