FRANKFURT AM MAIN, GERMANY - OCTOBER 18: King Willem-Alexander of Netherlands and King Philippe of Belge at the opening ceremony of the 2016 Frankfurt Book Fair (Frankfurter Buchmesse) on October 18, 2016 in Frankfurt am Main, Germany. The 2016 fair, which is among the world's largest book fairs, will be open to the public from October 19-23. (Photo by Hannelore Foerster/Getty Images)
