This is a 1 cent stamp of the series of stamps that were issued in 1955.
Even though this stamp is pretty old, it is still quite common and mint stamps like these can be easily gotten from ebay and stuff.
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It is indeed appropriate that are joint issue should feature bridges on stamps. Bridges serve to connect two land masses that are separated by water or a river. It signifies a closing in the gap and tightening of relations between two lands.
The bridges depicted here are found in Singapore and Philippines.