The stone walls of Intramuros, Manila, are 8m thick
The Walled City of Intramuros was begun in 1574. The 4 kilometer (2.5 mile) wall which runs around the perimeter was started in 1584 an took 6 years to complete. The Chinese were forced to work on the wall. When the wall was complete, the only access to the Walled City was through 7 gates. Intramuros was the Spanish Capital of the Philippines.