HANOVER, GERMANY - APRIL 24:  German chancellor Angela Merkel and U.S. President Barack Obama are seen on stage at the opening evening of the Hannover Messe trade fair on April 24, 2016 in Hanover, Germany. Obama met with German Chancellor Angela Merkel in Hanover earlier in the day and is scheduled to tour exhibition halls at the fair tomorrow. Hannover Messe is the world's largest industrial trade fair.  (Photo by Alexander Koerner/Getty Images)