. ♪ this is a german piano, an alexander herrmann. i bought it in 1957, i think. german piano to compose my music. europeans call me the beethoven of vietnam, and quy, the master of sonatas. here, this is the certificate. it makes me proud. ♪ nowadays, the world is dominated by american music. everyone performs pop, rap, and other kinds of music, which i think are a bit too disorderly. thank you for visiting me. i hope you enjoy the rest of your stay in vietnam. ♪ >> what a charming man. now bio-invaders sound like an , army. in fact, they often feel like one to native species. they can arrive from all over. it's more than just coincidence that the main routes for bio-invaders pretty much match -- pretty much look like a global transport map. these stowaways come at a price, causing an estimated 1 trillion euros in damage every year. some 12,000 such alien species live in the european union alone, with some of them causing serious damage. tunisia is currently having to learn to deal with an influx of jellyfish -- a pest for fishermen and tourists alike. scientists