One of the major highlights of Istanbul, the Topkapi Palace was built between 1459 and 1465 by the Ottomans just after their final conquest of Constantinople. This palace was the seat of power of the Ottoman Empire for 400 years. The palace is laid out around four courtyards, the first courtyard being outside the main gate.
The palace is located just to the northeast of the Haghia Sophia, and commands wonderful views of the Bosphorus Strait from the innermost (Fourth) courtyard.
Allow at least 3 hours to visit the palace, which offers (in addition to a number of palace rooms) several museums displaying the amassed wealth of the sultans over the centuries, including a treasury with stunning precious jewels, another containing weapons, and separate museums with manuscripts and a very interesting collection of clocks. No pictures are allowed in the museums.
Numerous items which belonged to the Prophet Mohammed are found in the Pavilion of the Holy Mantle, which makes the Topkapi Palace one of the most sacred pilgrimage sites of the Islamic faith.
The Harem rooms provide some insight into life in the palace. The Harem contained about 1,000 women (essentially slaves) brought from all over the Ottoman Empire. Their dream was to become a favorite of the sultan and to bare him a son which might lead to marriage and higher status. The Harem was ruled by the sultan’s mother, who was the most powerful woman at the palace.
A visit to the palace requires two separate fees and tickets, unless you get the Museum Pass in Istanbul which is good for 72 hours and allows entry to multiple sites and immediate access to the sites without waiting in line. The cost of the pass is about $36 USD. There is a kiosk right outside the Haghia Sophia. The Topkapi Palace gets very crowded with tour groups, so I highly suggest arriving before the palace opens. We were the first ones into the Harem and had the rooms to ourselves.
References: Plaques throughout the Topkapi Palace and DK Eyewitness Travel Turkey.