At the easternmost point of the peninsula stands the restored Topkapi Palace, once the home of the Ottoman sultans and now a museum. The picturesque Galata pontoon bridge, lined with shops and cafes, crosses the Golden Horn to the Galata business district. Both Islam and Christianity have dominated the city at different times in its history. The Muslim sultans of the Ottoman Empire built many famous mosques including that of Sultan Achmet, the Blue Mosque, which was constructed between 1609 and 1616. It later became a mosque but is now a museum.
Economic activity is linked to trade and commerce.
The Grand Bazaar, or Covered Bazaar, features more than 4,000 shops that sell gold jewelry, carpets, and ceramic, copper, and brass ware. Istanbul is Turkey's largest port and center of wholesale commerce and transportation. The excellent natural harbor it maintained for centuries in the Golden Horn and the city's key location on the trade routes between Europe and Asia made it a major transshipping point. Emperor Constantine proclaimed it his capital in AD 330 and renamed it Constantinople. He and his successors built walls, aqueducts, cisterns, and public fountains.