Topkapi Palace
If there is one absolute must-see in Istanbul, it has to be the Topkapi Palace, home to generations of sultans and their wives, who were closeted in the famous harem. A collection of lush green courtyards and delicate kiosks, the Topkapi boasts a treasury to put the crown jewels in the shade, as well as views to die for over the Sea of Marmara, Bosphorus and Golden Horn. The secretive harem – really just the family quarters – is a warren of lushly-tiled rooms wrapped round a gem of a Turkish bath. Try to visit on a day when no cruise ship is in town to avoid the worst of the crowds.