I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "Turkey: The torch relay leg in Istanbul, held on April 3, started on Sultanahmet Square and finished in Taksim Square. Uyghurs living in Turkey protested at Chinese treatment of their compatriots living in Xinjiang. Several protesters who tried to disrupt the relay were promptly arrested by the police."? 

The leg began where?