A boat (back L) transporting Britain's King Charles III, Hamburg's Mayor Peter Tschentscher, German President Frank-Walter Steinmeier and other participants leaves for a Green Energy Boat Trip of the harbour in Hamburg, northern Germany on March 31, 2023. - Britain's Royal Couple is on a three-day tour in Germany for Charles' first state visit as king, with the trip billed as "an important European gesture" to maintain strong ties after Brexit. (Photo by Axel Heimken / AFP)