In 1838, businessman Thomas McKay built an 11-room villa in the countryside outside Bytown, now Ottawa. In 1866, the house and surrounding estate became the official residence and workplace of Canada’s governor general. Here, at Rideau Hall, the governor general welcomes visiting heads of state and other dignitaries. If you take a walk around the grounds, you’ll find trees planted by many of these visitors. People such as Nelson Mandela, Emperor Akihito of Japan and Her Majesty Queen Elizabeth II have all planted trees on the grounds.