When you visit İstanbul, there are few sights you must see and Topkapı is definitely one of them.
Topkapı Palace was the residence of the Ottoman sultans. And also it was the administrative and educational center of the state. The palace used for state occasions and royal entertainments too. If you walk through the alleys of the palace, you will feel the spirit of the Ottoman culture.
And to see the harem will be a different experience to understand the century of Ottomans and feeling like you are one of the people in that time. The amazing architecture is also beautiful in winter afternoons. But if you like walking in the gorgeous gardens and enjoying the view of the Bosphorus, it is better to go there in a good weather. And if you are lucky enough, you can see the jewelry displays. In the Topkapı palace, you can find a small museum which sells souvenirs. You can buy some souvenirs or you can wear traditional Turkish clothes to feel like an Ottoman and take photos with them.