Japan’s Emperor Naruhito and Empress Masako are on a state visit to the United Kingdom. On Monday, the Emperor visited a place he has developed a fondness for: the River Thames.

He went to see the Thames Barrier, the flood control gates that have protected London for more than four decades. He studied the history of the waterway during postgraduate research at the University of Oxford soon after the gates were built. He recounted that period in his memoir, “The Thames and I,” along with other experiences, including going to pubs.

Later in the day, the Emperor moved on to a reception, where he was welcomed by hundreds of people, including those at the Japan Society, who have fostered relations through business, the arts and academia.

Emperor Naruhito gave a speech in which he said it is the connections between people that drive societies forward and which create the foundations for exchanges between countries. He said he is especially happy to see young people taking part in such experiences and that he hopes to see even more friendship and goodwill.

Emperor Naruhito and Empress Masako will meet on Tuesday with King Charles and Queen Camilla. They will attend a state dinner at Buckingham Palace.