Down in the old walled city section of Manila, known as Intramuros, is the impressive church and monastery of San Augustin, which dates back to 1586. It has survived floods, earthquakes, lootings, and WW2 bombs. The ceiling is a masterful tromph l'oeil creation and the many carved features are astounding. The former monastery is now given over to a museum of all things pertaining to catholic nic-nakery.
In a city very thin on touristic high lights, this surely should be on your to do list. We only had a half hour run through between appointments which was unfortunately not enough.
San Augustin is on General Luna Street in Intramuros.
Ceck it out.