This is the oldest church in the Philippines and also the only building left intact in Intramuros after World War 2. Visit it for those reasons - and for the fantastic trompe l'oeil frescoed ceilings. You have to time your visit during masses, else the doors are closed. This would be 630 to 730 in the mornings and 530 to 630 in the afternoons. It's also very popular for weddings, so you can also peep in should you chance upon one.
Manila, Metro Manila, Philippines