Intramuros

Intramuros, located along the southern bank of the Pasig River, was built by the Spanish in the 16th century and is the oldest district of the city of Manila, the capital of the Philippines. Its name, taken from the Latin, intra muros, literally "Within the walls", meaning within the wall enclosure of the city/fortress, also describes its structure as it is surrounded by thick, high walls and moats. During the Spanish Period, Intramuros was considered Manila itself.

Here are two good links describing Intramuros:
http://www.tourism.gov.ph/intramuros/intramuros.htm

http://en.wikipedia.org/wiki/Intramuros