1 Which river is the world's longest? 2 In which country does the main headwater of the Amazon River have its source? 3 Who scored a 1993 US No1 album with River of Dreams? 4 In Greek mythology, the water from which river in the underworld was said to cause complete forgetfulness? 5 Which river marks the border between Mexico and Texas? 6 Who won best actor at the 2004 Academy Awards for his role in Mystic River? 7 In which two countries do the Tagus, Gaudiana and Douro rivers flow? 8 Who composed the waltz The Blue Danube? 9 In which country is Europe's longest river, the Volga? 10 Which American author said: 'Denial ain't just a river in Egypt'? Solution: 1 The Nile 2 Peru 3 Billy Joel 4 The Lethe 5 The Rio Grande (aka the Rio Bravo del Norte) 6 Sean Penn 7 Spain and Portugal 8 Johann Strauss II 9 Russia 10 Mark Twain.