Topkapi Palace

For nearly four hundred years, this sprawling complex on Seraglio Point was the nerve center of an empire that stretched from Budapest to Baghdad. Sultan Mehmed the Conqueror began building Topkapi in 1459, just six years after conquering Constantinople, and what started as a relatively modest administrative center eventually grew into a 700,000-square-meter labyrinth of courtyards, pavilions, kitchens, and one of history's most infamous harems.

The Harem alone contained over 400 rooms, and at its peak housed up to 300 concubines, the sultan's mother (the Valide Sultan, who often held more real power than her son), and an army of eunuch guards. The corridors were designed so that no one could see from one section into another — privacy was architecture. The Imperial Treasury holds the 86-carat Spoonmaker's Diamond, surrounded by 49 smaller diamonds. Legend says it was found in a rubbish heap and traded for three spoons by a man who had no idea what he had.

The palace kitchens once employed 800 cooks who prepared meals for up to 10,000 people daily, including an elaborate hierarchy of cuisine — the sultan ate different food from his courtiers, who ate differently from the guards. The kitchens now house one of the world's finest collections of Chinese celadon porcelain, numbering over 10,000 pieces, because the Ottomans believed celadon would change color in the presence of poison.

Topkapi stopped being the primary royal residence in 1853 when the sultans moved to the flashy European-style Dolmabahçe Palace, but by then it had already witnessed 25 sultans, countless intrigues, and at least one strangling with a bowstring. It became a museum in 1924, one of the first acts of the new Turkish Republic.