Detailed Instructions: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Q: With Constantinople as its capital and control of lands around the Mediterranean basin, the Ottoman Empire was at the centre of interactions between the Eastern and Western worlds for six centuries. Following a long period of military setbacks against European powers, the Ottoman Empire gradually declined into the late nineteenth century. The empire allied with Germany in the early 20th century, with the imperial ambition of recovering its lost territories, joining in World War I to achieve this ambition on the side of Germany and the Central Powers. While the Empire was able to largely hold its own during the conflict, it was struggling with internal dissent, especially with the Arab Revolt in its Arabian holdings. Starting before the war, but growing increasingly common and violent during it, major atrocities were committed by the Ottoman government against the Armenians, Assyrians and Pontic Greeks. The Empire's defeat and the occupation of part of its territory by the Allied Powers in the aftermath of World War I resulted in the emergence of a new state, Turkey, in the Ottoman Anatolian heartland following the Turkish War of Independence, as well as the founding of modern Balkan and Middle Eastern states and the partitioning of the Ottoman Empire.
A:
What was the capital of the Ottoman empire?