<p>This massive mansion, built in 1863 for shipping magnate Sir Hugh Allan, was once considered among Canada's grandest homes. Its history took a dark turn when, as part of the Allan Memorial Institute (a psychiatric hospital affiliated with McGill University), it became a site for the CIA's controversial MKUltra mind-control experiments during the 1950s and 60s. Today, it remains part of McGill, a reminder of the complex and sometimes unsettling histories hidden within stately architecture.</p>
