Treewind/anahata mentioned bells, good suggestion. On a slightly different tack, surely the bells must be the oldest instruments still in use? I used to live in Claughton in Lunesdale, and the bell in the tiny little church there was made in 1296. There may be older ones in England, but I haven't heard of one. That's an impressive age for an instrument in regular use. Maybe it should be the national instrument?
Actually, though, surely things like national instruments and national constitutions and national values are only for foreigners?