Parliament Hill is a limestone outcrop with a gently sloping top that was originally covered in primeval forest of beech and hemlock. For hundreds of years, the hill served as a landmark on the Ottawa River for First Nations and, later, European traders, adventurers, and industrialists, to mark their journey to the interior of the continent. After Ottawa,then called Bytown, was founded, the builders of the Rideau Canal used the hill as a location for a military base, naming it Barrack Hill. A large fortress was planned for the site but never built, and by the mid-19th century the hill had lost its strategic importance.