Istanbul, the largest city in Turkey, was the capital of the Byzantine and Ottoman empires. The Bosphorus straits divides the city into a part that sits on the European continent, and a larger part on the continent of Asia. The militarily and economically strategic position of the city, on the western portion of the Silk Road, and on the shipping route between the Aegean and Black Seas, has kept it cosmopolitan and prosperous since its foundation 660 BCE, when it was called Byzantium. In 330 it became Constantinople, the capital of the Roman Empire, named for Emperor Constantine the Great. The Ottomans conquered the city in 1453/857 AH and renamed the city Istanbul. It served as their capital until Ankara became the capital of the modern nation of Turkey.
This set of plans on Archnet is a complete set of the Plan d'Assurance de Constantinople (Insurance Plan of Constantinople), issued by Charles E. Goad, a London-based civil engineer, in three volumes between 1904-1906. The fire insurance maps show building footprints, usages, and materials in the city of Istanbul.
Volume I, Stamboul, was published in September 1904. It included sheets 1-20 at 1/600 scale, with a key map, index sheet, and "Explanation of Signs" sheet.
Volume II, Pera & Galata, was published in December 1905. It included sheets 24-30 & 35-45 at 1/600 scale, with a key map and two index sheets.
Volume III, Kadi-Keui, was published in April 1906. It included sheets 51-64 at a 1/1,200 scale, with a key map and index sheet.
Individual sheets can be downloaded from the list below.