Philippines' ancient castle in the center of Manila city.

San Diego Castle is located in Manila, Philippines. It is an ancient castle that was once the political, military, and cultural center of the Philippines. The castle was built during the Spanish colonial period and was the first city established by the Spanish in Manila after conquering the Philippines. San Diego Castle is the oldest city in Philippine history and the early urban core of Manila. San Diego Castle began construction in the mid-16th century and was a colonial city of Spain in the Philippines. It was surrounded by high walls and fortresses to protect the Spanish authorities and colonizers from external invasion. There are many buildings from the Spanish era and ancient churches in the castle, such as the Church of St. Augustine, the Church of St. Francis, and the Church of St. Dominic. San Diego Castle was once the center of political and military power in the Philippines and one of the most important colonial cities of Spain in Asia. However, in the late 19th and early 20th centuries, San Diego Castle lost its political and economic importance and suffered severe war damage during World War II. Today, San Diego Castle is regarded as an important historical and cultural landmark in Manila, attracting a large number of tourists and local residents to visit. The castle has museums, art galleries, and cultural venues to showcase the rich heritage of Philippine history and culture. Visitors can wander around the castle, admire the ancient buildings and walls, experience the historical atmosphere of the Spanish era, and enjoy the magnificent panoramic view of the castle.