The National Museum of the Philippines is located in Manila, the capital of the Philippines in the building of the Old Congress Building. The building was intended to be the home of the National Library of the Philippines. Another building for the Philippine Legislature was meant to be built south of the library, but building plans were cancelled and the Legislature moved into the library building in 1926. From them on the building was known as the Legislature Building.
The building was commemorated on a set of stamps in the 1920s, which is pretty iconic for any history buff or stamp collector. Check out this blog for more information on these stamps.
The building became the home of the National Assemble of the Philippines after the Commonwealth of the Philippines was inaugurated in 1935. The Congress of the Philippines also occupied the floors of the building. The building was destroyed by Japanese forces during World War II, and reconstruction began in 1949. The building was rebuilt almost entirely by memory.
It was then used as the Congress Building until the Congress dissolved in the 1970s. The building then became the home of the Prime Minister of the Philippines. The House of Representatives and the Senate moved elsewhere.
The National Historical Commission of the Philippines declared the building as a "National Historical Landmark" and is currently the National Museum of the Philippines.