BERLIN, GERMANY - JUNE 24:  German President Joachim Gauck and partner Daniela Schadt, Queen Elizabeth II and Prince Philip, the Duke of Edinburgh, ride a boat on the Spree River on the second day day of the royal couple's four-day visit to Germany on June 24, 2015 in Berlin, Germany. The Queen and Prince Philip are scheduled to visit Berlin, Frankfurt and the concentration camp memorial at Bergen-Belsen during their trip, which is their first to Germany since 2004.  (Photo by Carsten Koall/Getty Images)