After Sultan Ahmed Shah I took over Karnavati and rechristened it Ahmedabad, the city continued flourishing for decades. By 1487, it was a popular centre of power and Sultan Shah's grandson, Mahmud Begada, decided to fortify it against invasion. A wall with a 10-km-circumference was constructed to encircle the city and protect it from enemies. Originally, the wall had 12 gates and 189 bastions. Over time 6,000 ramparts were added to this. However, as the city spread to the other side of the river bank, most of the walls were removed. Today, only 12 gates stand with a section of the wall along the riverfront. The area within the old wall boundary is classified as Old city or Walled city and its narrow, bustling roads are easily distinguishable. The 12 gates standing, in clockwise count from the northwest corner of the city are: Shahpur Gate, Delhi Gate, Dariapur Gate, Prem Gate, Kalupur Gate, Panch Kuva Gate, Sarangpur Gate, Raipur Gate, Astodia Gate, Mahudha Gate, Jamalpur Gate, Khanjia Gate, Raikhad Gate, Ganesh Gate and Ram Gate. Each of the gates has carvings and calligraphy on them. Some even have balconies still standing firm.