4 ideas
In 1570 Martin de Goiti's Spanish expedition clashed with Rajah Sulayman's fortified Muslim settlement at the mouth of the Pasig, and the town was burned. In 1571 Miguel Lopez de Legazpi proclaimed the Spanish city of Manila on the same site, so the colonial capital was built directly on top of a pre-existing Tagalog-Bornean trading polity rather than on empty ground.
Manila's settlements, trade routes, neighborhoods and even its name (from the nilad plant that grew along the Pasig's banks) follow the river and the bay rather than roads or walls. Treating the waterway as the city's original spine explains why power, commerce and population concentrated where they did long before any colonial planner arrived.
Manila's importance came less from its being a seat of government than from its position as an entrepôt: first in Asian coastal trade, then as the Asian terminus of the Manila-Acapulco galleon linking Chinese goods to Spanish American silver. That trade made the Chinese merchant community indispensable to the city's economy, even as colonial authorities confined it to the Parian and periodically turned on it with violence.
In February 1945, American forces fought to retake Manila while Japanese troops massacred civilians. Street fighting and artillery destroyed the walled city of Intramuros and much of the surrounding historic districts, and roughly 100,000 civilians died. Manila became one of the most devastated cities of the Second World War, and centuries of built heritage were largely lost in a single month.