useless trivia: What Word Means: Of Finns And Magyars - A Uralic Language?

Questions

In which ocean would you find the islands of Sao Tome and Principe?

"Vissi D'Arte" is a famous aria from a Puccini opera in which the eponymous heroine is an opera singer. Name the opera?

What was the title of Agatha Christie's first Hercule Poirot novel?

In which European city are the headquarters of OPEC (Organisation of Petroleum Exporting Countries)?

Which sportswear company was founded in Germany by a certain Dr. Dassler?