Que­bec was found­ed by the French explor­er Cham­plain in the ear­ly 17th cen­tu­ry. It is the only North Amer­i­can city to have pre­served its ram­parts, togeth­er with the numer­ous bas­tions, gates and defen­sive works which still sur­round Old Que­bec. The Upper Town, built on the cliff, has remained the reli­gious and admin­is­tra­tive cen­tre, with its church­es, con­vents and oth­er mon­u­ments like the Dauphine Redoubt, the Citadel and Chateau Fron­tenac. Togeth­er with the Low­er Town and its ancient dis­tricts, it forms an urban ensem­ble which is one of the best exam­ples of a for­ti­fied colo­nial city.