Signal Hill has long been used for observation and communication. Here, signalmen surveyed the ocean for ships headed into St. John's harbour, years before the advent of ship-to-shore radio. From signal masts high atop the Hill, flags conveyed information on approaching vessels to military and mercantile interests in St. John's. Merchants then had plenty of time to prepare their docks for incoming vessels.

With its obvious strategic location, Signal Hill became the site of harbour defences from the 18th century through the Second World War. The last battle of the Seven Years' War in North America was fought here in 1762. Ruins of later 19th -century military buildings can still be seen. The first known defences of St. John's harbour were shore batteries constructed on either side of the Narrows to protect St. John's against naval attack. St. John's fell to the French marching overland from Placentia in 1696, 1705 and again in 1709. In 1713, the Treaty of Utrecht recognized British sovereignty over Newfoundland, temporarily ending conflict between Britain and France.

In June 1762, the French again captured St. John's, this time to strengthen France's bargaining position after the loss of Louisbourg and Quebec. In September, the British reclaimed the Town when Lieutenant-Colonel William Amherst advanced on St. John's from Torbay. By taking Signal Hill first, Amherst had a strategic advantage over the French at Fort William. They surrendered after a night of mortar bombardment from the Hill. Fort Townsend was built in the 1770s, out of range of Signal Hill's guns.

The fortification of Signal Hill began during the Napoleonic Wars. Queen's, Wallace's, Waldegrave, Duke of York's, Quidi Vidi Pass and Carronade Batteries date from this period. The Hill was the place of ultimate retreat for the garrison at Forts William and Townsend. An impressive show of strength here in 1796 deterred a French fleet, under Admiral de Richery.

New barracks were built at the Queen's Battery and the summit in the 1830s, and the hill was fortified again during the American Civil War. In the First World War a contingent of Newfoundland Legion of Frontiersmen manned Fort Waldegrave in the Narrows. During the Second World War, the United States maintained anti-aircraft artillery, coastal defence guns and a mobile battery on the Hill.

Three different hospitals were operated on the Hill between 1870 and 1920; all were destroyed by fire. It was in one of these facilities, the Diphtheria and Fever Hospital, that Guglielmo Marconi received the first transatlantic wireless signal on December 12, 1901.

Between 1898 to 1900, Cabot Tower, St. John's most visible landmark, was constructed in honour of Queen Victoria's Diamond Jubilee, and the 400th anniversary of John Cabot's ''Voyage of Discovery.'' The Tower was used for signalling until 1960. Today the tower contains exhibits describing Marconi's wireless reception at Signal Hill and a gift shop.

One of the Site's most appealing attractions is an extensive walking trail, called the Lookout Trail, on the summit of Signal Hill. On the St. John's side, a low wall suggests the wooden stockade wall and half-moon batteries which protected the summit from attack. Towards the ''Narrows'' a stone walled viewing deck represents the area where the Duke of York's Battery once stood. Other viewing bays on the seaward side of the summit provide marvellous views of the Atlantic ocean and the rugged coastline. Along the trail, a number of interpretive panels provide insight into the history, geography and climate that have played such a critical role in defining our culture. The Lookout Trail is a joint project, funded by the Johnson Family Foundation and Parks Canada. The Johnson Family Foundation is a registered charitable foundation which ''initiates and supports measures that recognize, emphasize, clarify, preserve and sustain the history, traditions, nature and scenery of the Province of Newfoundland.''

Signal Hill and Cabot Tower have come to symbolize St. John's historic past. Signal Hill National Historic Site will introduce you to many of the most important and interesting aspects of that history.